diff --git a/bsp/at32/libraries/rt_drivers/drv_emac.c b/bsp/at32/libraries/rt_drivers/drv_emac.c
index 0f016b4ae9192301a70b92f5e208166393d2e8b9..acbe3a0d27ca24d5a02fd2315b09cf6119acf73d 100644
--- a/bsp/at32/libraries/rt_drivers/drv_emac.c
+++ b/bsp/at32/libraries/rt_drivers/drv_emac.c
@@ -6,6 +6,8 @@
  * Change Logs:
  * Date           Author       Notes
  * 2022-05-16     shelton      first version
+ * 2022-07-11     shelton      optimize code to improve network throughput
+ *                             performance
  */
 
 #include "drv_emac.h"
@@ -22,8 +24,8 @@
 #define CRYSTAL_ON_PHY                  0
 
 /* emac memory buffer configuration */
-#define EMAC_NUM_RX_BUF                 4    /* 0x1800 for rx (4 * 1536 = 6k)      */
-#define EMAC_NUM_TX_BUF                 2    /* 0x0600 for tx (2 * 1536 = 3k)      */
+#define EMAC_NUM_RX_BUF                 5    /* rx (5 * 1500) */
+#define EMAC_NUM_TX_BUF                 5    /* tx (5 * 1500) */
 
 #define MAX_ADDR_LEN                    6
 
@@ -49,8 +51,6 @@ extern emac_dma_desc_type *dma_rx_desc_to_get, *dma_tx_desc_to_set;
 static rt_uint8_t *rx_buff, *tx_buff;
 static struct rt_at32_emac at32_emac_device;
 static uint8_t phy_addr = 0xFF;
-static struct rt_semaphore tx_wait;
-static rt_bool_t tx_is_waiting = RT_FALSE;
 
 #if defined(EMAC_RX_DUMP) || defined(EMAC_TX_DUMP)
 #define __is_print(ch) ((unsigned int)((ch) - ' ') < 127u - ' ')
@@ -123,7 +123,6 @@ static void phy_reset(void)
     rt_thread_mdelay(2000);
 }
 
-
 /**
   * @brief phy clock config
   */
@@ -143,7 +142,6 @@ static void phy_clock_config(void)
     gpio_init_struct.gpio_pins = GPIO_PINS_8;
     gpio_init(GPIOA, &gpio_init_struct);
 
-
     /* 9162 clkout output 25 mhz */
     /* 83848 clkout output 50 mhz */
 #if defined (SOC_SERIES_AT32F407)
@@ -444,22 +442,15 @@ static rt_err_t rt_at32_emac_control(rt_device_t dev, int cmd, void *args)
   */
 rt_err_t rt_at32_emac_tx(rt_device_t dev, struct pbuf *p)
 {
+    rt_err_t ret = RT_ERROR;
     struct pbuf *q;
     rt_uint32_t offset;
 
-    while ((dma_tx_desc_to_set->status & EMAC_DMATXDESC_OWN) != RESET)
+    if ((dma_tx_desc_to_set->status & EMAC_DMATXDESC_OWN) != RESET)
     {
-        rt_err_t result;
-        rt_uint32_t level;
-
-        level = rt_hw_interrupt_disable();
-        tx_is_waiting = RT_TRUE;
-        rt_hw_interrupt_enable(level);
-
-        /* it's own bit set, wait it */
-        result = rt_sem_take(&tx_wait, RT_WAITING_FOREVER);
-        if (result == RT_EOK) break;
-        if (result == -RT_ERROR) return -RT_ERROR;
+        LOG_D("buffer not valid");
+        ret = ERR_USE;
+        goto __error;
     }
 
     offset = 0;
@@ -499,6 +490,18 @@ rt_err_t rt_at32_emac_tx(rt_device_t dev, struct pbuf *p)
     dma_tx_desc_to_set = (emac_dma_desc_type*) (dma_tx_desc_to_set->buf2nextdescaddr);
 
     return ERR_OK;
+
+__error:
+    if (emac_dma_flag_get(EMAC_DMA_UNF_FLAG) != (uint32_t)RESET)
+    {
+        /* clear underflow ethernet dma flag */
+        emac_dma_flag_clear(EMAC_DMA_UNF_FLAG);
+
+        /* resume dma transmission*/
+        EMAC_DMA->tpd = 0;
+    }
+
+    return ret;
 }
 
 /**
@@ -581,24 +584,6 @@ void EMAC_IRQHandler(void)
     /* enter interrupt */
     rt_interrupt_enter();
 
-    /* clear received it */
-    if(emac_dma_flag_get(EMAC_DMA_NIS_FLAG) != RESET)
-    {
-        emac_dma_flag_clear(EMAC_DMA_NIS_FLAG);
-    }
-    if(emac_dma_flag_get(EMAC_DMA_AIS_FLAG) != RESET)
-    {
-        emac_dma_flag_clear(EMAC_DMA_AIS_FLAG);
-    }
-    if(emac_dma_flag_get(EMAC_DMA_OVF_FLAG) != RESET)
-    {
-        emac_dma_flag_clear(EMAC_DMA_OVF_FLAG);
-    }
-    if(emac_dma_flag_get(EMAC_DMA_RBU_FLAG) != RESET)
-    {
-        emac_dma_flag_clear(EMAC_DMA_RBU_FLAG);
-    }
-
     /* packet receiption */
     if (emac_dma_flag_get(EMAC_DMA_RI_FLAG) == SET)
     {
@@ -610,13 +595,25 @@ void EMAC_IRQHandler(void)
     /* packet transmission */
     if (emac_dma_flag_get(EMAC_DMA_TI_FLAG) == SET)
     {
-        if (tx_is_waiting == RT_TRUE)
+        emac_dma_flag_clear(EMAC_DMA_TI_FLAG);
+    }
+
+    /* clear normal interrupt */
+    emac_dma_flag_clear(EMAC_DMA_NIS_FLAG);
+
+    /* clear dma error */
+    if(emac_dma_flag_get(EMAC_DMA_AIS_FLAG) != RESET)
+    {
+        if(emac_dma_flag_get(EMAC_DMA_RBU_FLAG) != RESET)
         {
-            tx_is_waiting = RT_FALSE;
-            rt_sem_release(&tx_wait);
+            emac_dma_flag_clear(EMAC_DMA_RBU_FLAG);
+        }
+        if(emac_dma_flag_get(EMAC_DMA_OVF_FLAG) != RESET)
+        {
+            emac_dma_flag_clear(EMAC_DMA_OVF_FLAG);
         }
 
-        emac_dma_flag_clear(EMAC_DMA_TI_FLAG);
+        emac_dma_flag_clear(EMAC_DMA_AIS_FLAG);
     }
 
     /* leave interrupt */