Abstract: A design method of FIR filter which based on DSP is introduced. Firstly, a low-pass filter which meets the requirements is designed by Matlab, and the simulation result is given, and the filter coefficient is extracted. Then, the low-pass filter of two different frequency sine wave signals is achieved by indirect addressing mode of the circular buffer and double operation in the TMS320LF2407A. Contrasted simulation with hardware verification results, it shows that the filter can meet basically expected performance requirements. The practices and researches show that Matlab simulation which is introduced in DSP application technology experiment teaching, obtain good teaching effect and solve the problems of DSP application technology experiment teaching.