A system for processing decaying periodic physiological signals comprises at least a sensor, a physiological signal-digitizing device, and a digital-signal processing unit to establish a parameterized database according to Pji, Sji, the relationship between Pji and Sji and the change with respect to time or locations of the sensors on the human body for evaluating the physiological or mental conditions. The system is applicable to processing and utilizing the decaying periodic physiological signals, such as heartbeats, respiration and ECG.
