diff --git a/core-tests/src/server/server.cpp b/core-tests/src/server/server.cpp
index 7f4ce668a57..e3446c953b3 100644
--- a/core-tests/src/server/server.cpp
+++ b/core-tests/src/server/server.cpp
@@ -193,3 +193,36 @@ TEST(server, task_worker) {
     t1.join();
     serv.gs->task_workers.destroy();
 }
+
+TEST(server, max_connection) {
+    Server serv;
+
+    serv.set_max_connection(0);
+    ASSERT_EQ(serv.get_max_connection(), SW_MIN(SW_MAX_CONNECTION, SwooleG.max_sockets));
+
+    serv.set_max_connection(SwooleG.max_sockets + 13);
+    ASSERT_EQ(serv.get_max_connection(), SwooleG.max_sockets);
+
+    serv.set_max_connection(SwooleG.max_sockets - 13);
+    ASSERT_EQ(serv.get_max_connection(), SwooleG.max_sockets - 13);
+
+    uint32_t last_value = serv.get_max_connection();
+
+    serv.create();
+
+    serv.set_max_connection(100);
+    ASSERT_EQ(serv.get_max_connection(), last_value);
+}
+
+TEST(server, min_connection) {
+    Server serv;
+
+    serv.task_worker_num = 14;
+    serv.worker_num = 5;
+
+    serv.add_port(SW_SOCK_TCP, TEST_HOST, 0);
+
+    serv.set_max_connection(15);
+    serv.create();
+    ASSERT_EQ(serv.get_max_connection(), SwooleG.max_sockets);
+}
diff --git a/examples/cpp/test_server.cc b/examples/cpp/test_server.cc
index 4603e9050eb..4967fe82786 100644
--- a/examples/cpp/test_server.cc
+++ b/examples/cpp/test_server.cc
@@ -31,7 +31,7 @@ int main(int argc, char **argv) {
     serv.worker_num = 1;
 
     serv.factory_mode = SW_MODE_BASE;
-    serv.max_connection = 10000;
+    serv.set_max_connection(10000);
     // serv.open_cpu_affinity = 1;
     // serv.open_tcp_nodelay = 1;
     // serv.daemonize = 1;
diff --git a/include/server.h b/include/server.h
index f2337b64124..c0e86879e94 100644
--- a/include/server.h
+++ b/include/server.h
@@ -522,11 +522,6 @@ class Server {
     int worker_groupid = 0;
     void **worker_input_buffers = nullptr;
 
-    /**
-     * max connection num
-     */
-    uint32_t max_connection = 0;
-
     /**
      * worker process max request
      */
@@ -1102,6 +1097,12 @@ class Server {
     void init_signal_handler();
 
     void set_ipc_max_size();
+    void set_max_connection(uint32_t _max_connection);
+
+    inline uint32_t get_max_connection() {
+        return max_connection;
+    }
+    
     int create_pipe_buffers();
     int create_worker(swWorker *worker);
     void disable_accept();
@@ -1226,6 +1227,7 @@ class Server {
      */
     std::string document_root;
     std::mutex lock_;
+    uint32_t max_connection = 0;
 
     int start_check();
     void check_port_type(ListenPort *ls);
diff --git a/src/server/master.cc b/src/server/master.cc
index 1c8fc54c67a..c9b36068191 100644
--- a/src/server/master.cc
+++ b/src/server/master.cc
@@ -243,6 +243,24 @@ dtls::Session *Server::accept_dtls_connection(swListenPort *port, swSocketAddres
 }
 #endif
 
+void Server::set_max_connection(uint32_t _max_connection) {
+    if (connection_list != nullptr) {
+        swWarn("max_connection must be set before server create");
+        return;
+    }
+    max_connection = _max_connection;
+    if (max_connection == 0) {
+        max_connection = SW_MIN(SW_MAX_CONNECTION, SwooleG.max_sockets);
+    } else if (max_connection > SW_SESSION_LIST_SIZE) {
+        max_connection = SW_SESSION_LIST_SIZE;
+        swWarn("max_connection is exceed the SW_SESSION_LIST_SIZE, it's reset to %u", SW_SESSION_LIST_SIZE);
+    }
+    if (SwooleG.max_sockets > 0 && max_connection > SwooleG.max_sockets) {
+        max_connection = SwooleG.max_sockets;
+        swWarn("max_connection is exceed the maximum value, it's reset to %u", SwooleG.max_sockets);
+    }
+}
+
 int Server::start_check() {
     // disable notice when use SW_DISPATCH_ROUND and SW_DISPATCH_QUEUE
     if (factory_mode == SW_MODE_PROCESS) {
@@ -305,18 +323,6 @@ int Server::start_check() {
     if (worker_num < reactor_num) {
         reactor_num = worker_num;
     }
-    // max connections
-    uint32_t minimum_connection = (worker_num + task_worker_num) * 2 + 32;
-    if (max_connection < minimum_connection) {
-        max_connection = SwooleG.max_sockets;
-        swWarn("max_connection must be bigger than %u, it's reset to %u", minimum_connection, SwooleG.max_sockets);
-    } else if (SwooleG.max_sockets > 0 && max_connection > SwooleG.max_sockets) {
-        max_connection = SwooleG.max_sockets;
-        swWarn("max_connection is exceed the maximum value, it's reset to %u", SwooleG.max_sockets);
-    } else if (max_connection > SW_SESSION_LIST_SIZE) {
-        max_connection = SW_SESSION_LIST_SIZE;
-        swWarn("max_connection is exceed the SW_SESSION_LIST_SIZE, it's reset to %u", SW_SESSION_LIST_SIZE);
-    }
     // package max length
     for (auto ls : ports) {
         if (ls->protocol.package_max_length < SW_BUFFER_MIN_SIZE) {
@@ -714,6 +720,15 @@ int Server::create() {
         locations = new std::unordered_set<std::string>;
     }
 
+    uint32_t minimum_connection = (worker_num + task_worker_num) * 2 + 32;
+    if (ports.size() > 0) {
+        minimum_connection += ports.back()->socket_fd;
+    }
+    if (max_connection < minimum_connection) {
+        max_connection = SwooleG.max_sockets;
+        swWarn("max_connection must be bigger than %u, it's reset to %u", minimum_connection, SwooleG.max_sockets);
+    }
+
     if (factory_mode == SW_MODE_BASE) {
         return create_reactor_processes();
     } else {
diff --git a/src/server/reactor_process.cc b/src/server/reactor_process.cc
index 47d27b94aaf..89610c75d56 100644
--- a/src/server/reactor_process.cc
+++ b/src/server/reactor_process.cc
@@ -317,7 +317,7 @@ static int swReactorProcess_loop(swProcessPool *pool, swWorker *worker) {
     }
 #endif
 
-    reactor->max_socket = serv->max_connection;
+    reactor->max_socket = serv->get_max_connection();
 
     reactor->close = Server::close_connection;
 
diff --git a/src/server/reactor_thread.cc b/src/server/reactor_thread.cc
index 406b8cd5f8f..f0e5b2d8fb8 100644
--- a/src/server/reactor_thread.cc
+++ b/src/server/reactor_thread.cc
@@ -839,7 +839,7 @@ static int ReactorThread_init(Server *serv, Reactor *reactor, uint16_t reactor_i
     reactor->ptr = serv;
     reactor->id = reactor_id;
     reactor->wait_exit = 0;
-    reactor->max_socket = serv->max_connection;
+    reactor->max_socket = serv->get_max_connection();
     reactor->close = Server::close_connection;
 
     reactor->set_exit_condition(SW_REACTOR_EXIT_CONDITION_DEFAULT, [thread](Reactor *reactor, int &event_num) -> bool {
diff --git a/swoole_server.cc b/swoole_server.cc
index a261a7a1701..63ac01f3139 100644
--- a/swoole_server.cc
+++ b/swoole_server.cc
@@ -1117,7 +1117,7 @@ void php_swoole_server_before_start(swServer *serv, zval *zobject) {
         add_assoc_long(zsetting, "output_buffer_size", serv->output_buffer_size);
     }
     if (!zend_hash_str_exists(Z_ARRVAL_P(zsetting), ZEND_STRL("max_connection"))) {
-        add_assoc_long(zsetting, "max_connection", serv->max_connection);
+        add_assoc_long(zsetting, "max_connection", serv->get_max_connection());
     }
 
     uint32_t i;
@@ -2308,7 +2308,7 @@ static PHP_METHOD(swoole_server, set) {
     // max_connection
     if (php_swoole_array_get_value(vht, "max_connection", ztmp) || php_swoole_array_get_value(vht, "max_conn", ztmp)) {
         zend_long v = zval_get_long(ztmp);
-        serv->max_connection = SW_MAX(0, SW_MIN(v, UINT32_MAX));
+        serv->set_max_connection(SW_MAX(0, SW_MIN(v, UINT32_MAX)));
     }
     // heartbeat_check_interval
     if (php_swoole_array_get_value(vht, "heartbeat_check_interval", ztmp)) {