In this paper, we mainly introduce the serial communication between PC and FPGA and adopt the design principles of DDS phase accumulator to achieve small error of baud rate generator and provide the reliable data transmission. On PC, we use the Labview software to design control interface, which is responsible for sending the control command. The experimental results indicate that the communication is feasible, high stability. This design is applied to the control unit of waveform generator based on FPGA by inputting relevant data on PC such as waveform selection, frequency control, range control and phase control to realize the function of waveform selection, amplitude modulation, phase modulation and frequency modulation.