void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  //NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x2000);
  // 配置优先级分组，无抢占式优先级  
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
  
  // 配置USART1中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  // 配置USART2中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  // 配置USART3中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  // 2010-05-26, zhangxingjuan
  NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;  //中断通道
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;    //次优先级
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;       //通道中断使能
  NVIC_Init(&NVIC_InitStructure);                       //初始化中断
}


串口配置
void USART123_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;      // GPIO 初始化结构体
USART_InitTypeDef USART_InitStructure;      // USART 初始化结构体
                     
//***********Configure USART1 Tx Pin*********
GPIO_InitStructure.GPIO_Pin = GPIO_Tx1PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//***********Configure USART2 Tx Pin********
    GPIO_InitStructure.GPIO_Pin = GPIO_Tx2PIN;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//***********Configure USART3 Tx Pin*********
    GPIO_InitStructure.GPIO_Pin = GPIO_Tx3PIN;
GPIO_Init(GPIOB, &GPIO_InitStructure);
   //***********Configure USART1 Rx Pin*********
    GPIO_InitStructure.GPIO_Pin = GPIO_Rx1PIN;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//***********Configure USART2 Rx Pin*********
    GPIO_InitStructure.GPIO_Pin = GPIO_Rx2PIN;
GPIO_Init(GPIOA, &GPIO_InitStructure);
//***********Configure USART3 Rx Pin*********
    GPIO_InitStructure.GPIO_Pin = GPIO_Rx3PIN;
GPIO_Init(GPIOB, &GPIO_InitStructure);  
    //********USART1 configure para*********
USART_InitStructure.USART_BaudRate = 2400;
USART_InitStructure.USART_WordLength = USART_WordLength_9b;
USART_InitStructure.USART_StopBits = USART_StopBits_1;
USART_InitStructure.USART_Parity = USART_Parity_Even;
USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_Init(USART1,&USART_InitStructure);
  
/********USART2 configure para*********/
    USART_Init(USART2,&USART_InitStructure);  

/********USART3 configure para**********/
    USART_Init(USART3,&USART_InitStructure);
// 使能USART1、2、3的接收中断
    USART_ITConfig(USART1, USART_IT_RXNE, ENABLE);
USART_ITConfig(USART2, USART_IT_RXNE, ENABLE);
USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);
// 使能USART1、2、3  
USART_Cmd(USART1, ENABLE);
USART_Cmd(USART2, ENABLE);
USART_Cmd(USART3, ENABLE);         
}
/**
  * @描述：配置系统中断
  * @入口参数: 无
  */
  
void NVIC_Configuration(void)
{
  NVIC_InitTypeDef NVIC_InitStructure;
  //NVIC_SetVectorTable(NVIC_VectTab_FLASH, 0x2000);
  // 配置优先级分组，无抢占式优先级  
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_0);
  
  // 配置USART1中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  // 配置USART2中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART2_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  // 配置USART3中断优先级
  NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure);
  
  NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;  //中断通道
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 3;    //次优先级
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;       //通道中断使能
  NVIC_Init(&NVIC_InitStructure);                       //初始化中断
}

以上代码，串口发送数据没问题；但当接收数据时，无法进入USART中断（串口助手监视，是有数据的）；研究了半天那个英文编程手册，也没找的出路；望大虾解救。。。。。小弟刚接触STM的片子

，题目貌似写的不完整

建议你先检查硬件电路，用示波器看串口接收脚上是否有数据，有时候可能会由于虚焊之类的原因引起，如果是RS485的话，检查一下485芯片的接收使能（RE）是否打开

多谢楼上，问题今天已解决；确实是硬件问题！