//GPIO¶Ë¿ÚÉèÖÃ
    GPIO_InitTypeDef GPIO_InitStructure;
    USART_InitTypeDef USART_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
   
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2, ENABLE);    //ʹÄÜUSART2ʱÖÓ
    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOA, ENABLE);    //ʹÄÜGPIOAʱÖÓ

  GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_1);//¸´ÓÃÍÆÍìÊä³ö
    GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_1);//¸´ÓÃÍÆÍìÊä³ö
    //USART1_TX   GPIOA.2
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF; //¸´ÓÃÍÆÍìÊä³ö
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_Level_3; // I/OÊä³öƵÂÊ 50 MHz
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2;  //PA.2
    GPIO_Init(GPIOA, &GPIO_InitStructure);
    //USART1_RX   GPIOA.3
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_3;    //PA.3
    GPIO_Init(GPIOA, &GPIO_InitStructure);   

    //Usart2 NVIC ÅäÖÃ
    NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPriority=2 ;//ÓÅÏȼ¶3
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;            //IRQͨµÀʹÄÜ
    NVIC_Init(&NVIC_InitStructure);    //¸ù¾ÝÖ¸¶¨µÄ²ÎÊý³õʼ»¯VIC¼Ä´æÆ÷
  
   //USART ³õʼ»¯ÉèÖÃ

    USART_InitStructure.USART_BaudRate = bound2;//´®¿Ú²¨ÌØÂÊ
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;//×Ö³¤Îª8λÊý¾Ý¸ñʽ
    USART_InitStructure.USART_StopBits = USART_StopBits_1;//Ò»¸öֹͣλ

    USART_InitStructure.USART_Parity = USART_Parity_No;//ÎÞÆæżУÑéλ
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//ÎÞÓ²¼þÊý¾ÝÁ÷¿ØÖÆ
    USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;    //ÊÕ·¢Ä£Ê½

    USART_Init(USART2, &USART_InitStructure); //³õʼ»¯´®¿Ú2
    USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);//¿ªÆô´®¿Ú2½ÓÊÜÖжÏ
    USART_Cmd(USART2, ENABLE);  





u8 aa;   
void USART2_IRQHandler(void)                    //´®¿Ú1ÖжϷþÎñ³ÌÐò
{
    if(USART_GetITStatus(USART2, USART_IT_RXNE) != RESET)  //½ÓÊÕÖжÏ(½ÓÊÕµ½µÄÊý¾Ý±ØÐëÊÇ0x0d 0x0a½áβ)
        {
            
                aa =USART_ReceiveData(USART2);    //¶ÁÈ¡½ÓÊÕµ½µÄÊý¾Ý
        }
}      

楼主怎么没有请中断标志位？
USART_ClearITPendingBit(USART2,USART_IT_RXNE);