diff --git a/components/lwip/Kconfig b/components/lwip/Kconfig
index 420b78ed..af62dc5f 100644
--- a/components/lwip/Kconfig
+++ b/components/lwip/Kconfig
@@ -63,6 +63,12 @@ config LWIP_SOCKET_MULTITHREAD
         Enable the option can enable LWIP socket multithread and all
         function will be thread safe.
 
+config ENABLE_NONBLOCK_SPEEDUP
+    bool "Speed up send speed of nonblock TCP"
+    default n
+    help
+        Enable this option, send speed of nonblock TCP will increase obviously.
+
 config SET_SOLINGER_DEFAULT
     bool "set socket SO_LINGER default"
     default y
diff --git a/components/lwip/lwip/src/api/api_msg.c b/components/lwip/lwip/src/api/api_msg.c
index 6a0c539b..a5996969 100644
--- a/components/lwip/lwip/src/api/api_msg.c
+++ b/components/lwip/lwip/src/api/api_msg.c
@@ -371,13 +371,31 @@ sent_tcp(void *arg, struct tcp_pcb *pcb, u16_t len)
       lwip_netconn_do_close_internal(conn  WRITE_DELAYED);
     }
 
-    /* If the queued byte- or pbuf-count drops below the configured low-water limit,
-       let select mark this pcb as writable again. */
-    if ((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&
-      (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {
-      conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
-      API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);
+#if ESP_NONBLOCK
+    int dontblock = netconn_is_nonblocking(conn)
+                    | (conn->flags & NETCONN_FLAG_CHECK_WRITESPACE);
+
+    if (dontblock && conn->pcb.tcp) {
+      if (tcp_sndbuf(conn->pcb.tcp) != TCP_SND_BUF) {
+        tcp_output(conn->pcb.tcp);
+      }
+      if ((tcp_sndbuf(conn->pcb.tcp) > 0) &&
+        (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SND_QUEUELEN)) {
+        conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
+        API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);
+      }
+    } else {
+#endif /* ESP_NONBLOCK */
+      /* If the queued byte- or pbuf-count drops below the configured low-water limit,
+        let select mark this pcb as writable again. */
+      if ((conn->pcb.tcp != NULL) && (tcp_sndbuf(conn->pcb.tcp) > TCP_SNDLOWAT) &&
+        (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SNDQUEUELOWAT)) {
+        conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
+        API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);
+      }
+#if ESP_NONBLOCK
     }
+#endif /* ESP_NONBLOCK */
   }
 
   return ERR_OK;
@@ -1560,7 +1578,7 @@ lwip_netconn_do_writemore(struct netconn *conn  WRITE_DELAYED_PARAM)
 {
   err_t err;
   const void *dataptr;
-  u16_t len, available;
+  u16_t len = 0, available;
   u8_t write_finished = 0;
   size_t diff;
   u8_t dontblock;
@@ -1608,6 +1626,9 @@ lwip_netconn_do_writemore(struct netconn *conn  WRITE_DELAYED_PARAM)
       if (dontblock) {
         if (!len) {
           err = ERR_WOULDBLOCK;
+#if ESP_NONBLOCK
+          conn->flags |= NETCONN_FLAG_CHECK_WRITESPACE;
+#endif /* ESP_NONBLOCK */
           goto err_mem;
         }
       } else {
@@ -1687,6 +1708,17 @@ err_mem:
     conn->write_offset = 0;
     conn->state = NETCONN_NONE;
     NETCONN_SET_SAFE_ERR(conn, err);
+
+#if ESP_NONBLOCK
+    if (dontblock) {
+      if (tcp_sndbuf(conn->pcb.tcp) > 0 &&
+        (tcp_sndqueuelen(conn->pcb.tcp) < TCP_SND_QUEUELEN)) {
+        conn->flags &= ~NETCONN_FLAG_CHECK_WRITESPACE;
+        API_EVENT(conn, NETCONN_EVT_SENDPLUS, len);
+      }
+    }
+#endif /* ESP_NONBLOCK */
+
 #if LWIP_TCPIP_CORE_LOCKING
     if (delayed)
 #endif
diff --git a/components/lwip/port/esp8266/include/lwipopts.h b/components/lwip/port/esp8266/include/lwipopts.h
index fcc07147..82581753 100644
--- a/components/lwip/port/esp8266/include/lwipopts.h
+++ b/components/lwip/port/esp8266/include/lwipopts.h
@@ -66,6 +66,12 @@
 #define SOCKETS_MT
 #endif
 
+#if CONFIG_ENABLE_NONBLOCK_SPEEDUP
+#define ESP_NONBLOCK    1
+#else
+#define ESP_NONBLOCK    0
+#endif
+
 //#define SOCKETS_TCP_TRACE
 
 #define TCP_HIGH_SPEED_RETRANSMISSION CONFIG_TCP_HIGH_SPEED_RETRANSMISSION