diff --git a/components/drivers/include/drivers/serial.h b/components/drivers/include/drivers/serial.h
index b10dbe57d653eb27587355c900375258973367fb..edf05cfa1d0ec2194be3c4261e23d71661062eec 100644
--- a/components/drivers/include/drivers/serial.h
+++ b/components/drivers/include/drivers/serial.h
@@ -10,7 +10,9 @@
  * Change Logs:
  * Date           Author       Notes
  * 2012-05-15     lgnq         first version.
- * 2012-05-28     bernard      chage interfaces
+ * 2012-05-28     bernard      change interfaces
+ * 2013-02-20     bernard      use RT_SERIAL_RB_BUFSZ to define
+ *                             the size of ring buffer.
  */
 
 #ifndef __SERIAL_H__
@@ -43,9 +45,9 @@
 #define NRZ_NORMAL                      0       /* Non Return to Zero : normal mode */
 #define NRZ_INVERTED                    1       /* Non Return to Zero : inverted mode */
 
-#define UART_RX_BUFFER_SIZE             64
-#define UART_TX_BUFFER_SIZE             64
-#define SERIAL_RBUFFER_SIZE             64
+#ifndef RT_SERIAL_RB_BUFSZ
+#define RT_SERIAL_RB_BUFSZ				64
+#endif
 
 #define RT_DEVICE_CTRL_CONFIG           0x03    /* configure device */
 #define RT_DEVICE_CTRL_SET_INT          0x10    /* enable receive irq */
@@ -59,7 +61,7 @@
 #define RT_SERIAL_ERR_FRAMING           0x02
 #define RT_SERIAL_ERR_PARITY            0x03
 
-#define RT_SERIAL_TX_DATAQUEUE_SIZE     40
+#define RT_SERIAL_TX_DATAQUEUE_SIZE     2048
 #define RT_SERIAL_TX_DATAQUEUE_LWM      30
 
 /* Default config for serial_configure structure */
@@ -76,7 +78,7 @@
 
 struct serial_ringbuffer
 {
-    rt_uint8_t  buffer[SERIAL_RBUFFER_SIZE];
+    rt_uint8_t  buffer[RT_SERIAL_RB_BUFSZ];
     rt_uint16_t put_index, get_index;
 };
 
diff --git a/components/drivers/serial/serial.c b/components/drivers/serial/serial.c
index f73325a440806560eb8e4350963adc26aabb4c6b..d202dcc5654dc418284b8ed1198ffeee250a7dab 100644
--- a/components/drivers/serial/serial.c
+++ b/components/drivers/serial/serial.c
@@ -13,6 +13,8 @@
  * 2012-05-15     lgnq         modified according bernard's implementation.
  * 2012-05-28     bernard      code cleanup
  * 2012-11-23     bernard      fix compiler warning.
+ * 2013-02-20     bernard      use RT_SERIAL_RB_BUFSZ to define
+ *                             the size of ring buffer.
  */
 
 #include <rthw.h>
@@ -35,12 +37,12 @@ rt_inline void serial_ringbuffer_putc(struct serial_ringbuffer *rbuffer,
     level = rt_hw_interrupt_disable();
 
     rbuffer->buffer[rbuffer->put_index] = ch;
-    rbuffer->put_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+    rbuffer->put_index = (rbuffer->put_index + 1) & (RT_SERIAL_RB_BUFSZ - 1);
 
     /* if the next position is read index, discard this 'read char' */
     if (rbuffer->put_index == rbuffer->get_index)
     {
-        rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+        rbuffer->get_index = (rbuffer->get_index + 1) & (RT_SERIAL_RB_BUFSZ - 1);
     }
 
     /* enable interrupt */
@@ -56,7 +58,7 @@ rt_inline int serial_ringbuffer_putchar(struct serial_ringbuffer *rbuffer,
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
 
-    next_index = (rbuffer->put_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+    next_index = (rbuffer->put_index + 1) & (RT_SERIAL_RB_BUFSZ - 1);
     if (next_index != rbuffer->get_index)
     {
         rbuffer->buffer[rbuffer->put_index] = ch;
@@ -87,7 +89,7 @@ rt_inline int serial_ringbuffer_getc(struct serial_ringbuffer *rbuffer)
     if (rbuffer->get_index != rbuffer->put_index)
     {
         ch = rbuffer->buffer[rbuffer->get_index];
-        rbuffer->get_index = (rbuffer->get_index + 1) & (SERIAL_RBUFFER_SIZE - 1);
+        rbuffer->get_index = (rbuffer->get_index + 1) & (RT_SERIAL_RB_BUFSZ - 1);
     }
     /* enable interrupt */
     rt_hw_interrupt_enable(level);
@@ -101,7 +103,7 @@ rt_inline rt_uint32_t serial_ringbuffer_size(struct serial_ringbuffer *rbuffer)
     rt_base_t level;
 
     level = rt_hw_interrupt_disable();
-    size = (rbuffer->put_index - rbuffer->get_index) & (SERIAL_RBUFFER_SIZE - 1);
+    size = (rbuffer->put_index - rbuffer->get_index) & (RT_SERIAL_RB_BUFSZ - 1);
     rt_hw_interrupt_enable(level);
 
     return size;