diff --git a/bsp/at32/libraries/rt_drivers/drv_emac.c b/bsp/at32/libraries/rt_drivers/drv_emac.c
index acbe3a0d27ca24d5a02fd2315b09cf6119acf73d..df72259fda6755adf5ce5e5a83e45d016b91ef5b 100644
--- a/bsp/at32/libraries/rt_drivers/drv_emac.c
+++ b/bsp/at32/libraries/rt_drivers/drv_emac.c
@@ -8,6 +8,7 @@
  * 2022-05-16     shelton      first version
  * 2022-07-11     shelton      optimize code to improve network throughput
  *                             performance
+ * 2022-10-15     shelton      optimize code
  */
 
 #include "drv_emac.h"
@@ -355,6 +356,7 @@ static rt_err_t rt_at32_emac_init(rt_device_t dev)
 
     emac_control_para_init(&mac_control_para);
     mac_control_para.auto_nego = EMAC_AUTO_NEGOTIATION_ON;
+
     if(emac_phy_init(&mac_control_para) == ERROR)
     {
         LOG_E("emac hardware init failed");
@@ -376,8 +378,19 @@ static rt_err_t rt_at32_emac_init(rt_device_t dev)
     /* set emac dma tx link list */
     emac_dma_descriptor_list_address_set(EMAC_DMA_TRANSMIT, dma_tx_dscr_tab, tx_buff, EMAC_NUM_TX_BUF);
 
-    /* emac interrupt init */
+    emac_dma_para_init(&dma_control_para);
+    dma_control_para.rsf_enable = TRUE;
+    dma_control_para.tsf_enable = TRUE;
+    dma_control_para.osf_enable = TRUE;
+    dma_control_para.aab_enable = TRUE;
+    dma_control_para.usp_enable = TRUE;
+    dma_control_para.fb_enable = TRUE;
+    dma_control_para.flush_rx_disable = TRUE;
+    dma_control_para.rx_dma_pal = EMAC_DMA_PBL_32;
+    dma_control_para.tx_dma_pal = EMAC_DMA_PBL_32;
+    dma_control_para.priority_ratio = EMAC_DMA_2_RX_1_TX;
     emac_dma_config(&dma_control_para);
+    /* emac interrupt init */
     emac_dma_interrupt_enable(EMAC_DMA_INTERRUPT_NORMAL_SUMMARY, TRUE);
     emac_dma_interrupt_enable(EMAC_DMA_INTERRUPT_RX, TRUE);
     nvic_irq_enable(EMAC_IRQn, 0x07, 0);
@@ -467,6 +480,7 @@ rt_err_t rt_at32_emac_tx(rt_device_t dev, struct pbuf *p)
 #ifdef EMAC_TX_DUMP
     dump_hex(p->payload, p->tot_len);
 #endif
+
     /* prepare transmit descriptors to give to dma */
     LOG_D("transmit frame length :%d", p->tot_len);
 
diff --git a/bsp/at32/libraries/rt_drivers/drv_usart.c b/bsp/at32/libraries/rt_drivers/drv_usart.c
index 8e400bae580813f7a2d5390006902fc59238c57a..832dca02be15f17e4d153c7229ed12d52621c8eb 100644
--- a/bsp/at32/libraries/rt_drivers/drv_usart.c
+++ b/bsp/at32/libraries/rt_drivers/drv_usart.c
@@ -6,6 +6,7 @@
  * Change Logs:
  * Date           Author       Notes
  * 2022-05-16     shelton      first version
+ * 2022-10-15     shelton      optimize code
  */
 
 #include "drv_common.h"
@@ -228,7 +229,6 @@ static void usart_isr(struct rt_serial_device *serial) {
 
     if (usart_flag_get(usart_instance->usart_x, USART_RDBF_FLAG) != RESET) {
         rt_hw_serial_isr(serial, RT_SERIAL_EVENT_RX_IND);
-        usart_flag_clear(usart_instance->usart_x, USART_RDBF_FLAG);
     }
     else
     {