This paper illustrates the key principle and method of serial interface communication. Achieving the three kinds of communication methods, namely query methods, standard SCI interrupt mode, FIFO interrupt mode between PC and DSP. Under the same conditions, with receiving and transmitting the same data, using the FIFO interrupt mode is the least, is the most efficient communication efficiency and saves the CPU resources. when the data size is large, using this method is superior. In the interrupt FIFO method, in view of the power on sequence problem between PC and DSP, this paper proposes a method for reordering. After the experiment, the reliability of the method is verified.