Objective The present study was to perform research on the effect of different body posture on the radar echo signal to extract the vital signs parameters in the biological radar monitoring system. Methods The most common two positions lie on your back and sit were taken as the posture in the monitoring processing. The pose of radar echo signal analysis method was studied, and an improved adaptive cancellation filter algorithm was put forward. Results The center of the adaptive canceller output fi ltering signal frequency and synchronous monitoring heartbeat signal frequency was consistent under these two postures, and the strongest signal energy point was located in the center of the adaptive canceller output. Conclusion Effective vital signs parameters of breathing and heartbeat signals could be gained via using the improved adaptive cancellation fi lter algorithm under different postures.