Design of the differential code shift keying ( 2DPSK ) modulation and demodulation system work flow diagram, and the use of Matlab software on the system dynamic simulation. By using the simulation results, from the baseband signal waveform can be measured in digital signal transmission quality the system input and output waveform can be seen, a good simulation experiment. 2DPSK modulation and demodulation system simulation design, for further study of the communication based on Matlab simulation system laid solid foundation.-Design of the differential code shift keying ( 2DPSK ) modulation and demodulation system work flow diagram, and the use of Matlab software on the system dynamic simulation. By using the simulation results, from the baseband signal waveform can be measured in digital signal transmission quality　the system input and output waveform can be seen, a good simulation experiment. 2DPSK modulation and demodulation system simulation design, for further study of the communication based on Matlab simulation system laid solid foundation.