In recent years radar life detector is the rapid development product of information technology and Biomedical Engineering, and its core is to not contact with the human body, but to realize the detection of the parameters of human life which has a breakthrough, and to explore with full range. This paper first analyzes the principle of radar life detection system and the implementation scheme of each module technology. Based on this, DSP digital signal processing method is used to design the structure system of radar life detector. Further based on the DSP signal processing principle, PD distance tracking is used to approximately simulate the time domain of human heartbeat signal. The results show that the tracking effect that is under this structure is remarkable, which has provided technical support for the practice of the area to a certain extent.