I2C bus and RS-232 serial port are the important data communication interfaces between the MCU of embedded system and the peripheral equipment. The embedded system performance will be affected under complex electromagnetic environment by the improper disposal to the interfaces, which results in the low speed and reliability. According to the speed matching problems in current embedded programming, the paper designed two kinds of buffers, the double buffers and cycle single buffer, which separately solved the problems of the speed improvement of I2C bus and the serial transmission reliability of RS-232. The result of the experiment shows that communications of I2C bus and RS-232 serial port under complex electromagnetic environment can be of speediness and stabilization, and the ideal goal has been obtained.