A portable physiological signal detecting system is disclosed, which is capable of executing a physiological signal detecting process anywhere and any time in order to detect physiological signals of a user. The portable physiological signal detecting system comprises: a smartphone having a display unit and an audio input unit, a physiological signal detecting module having at least one physiological signal detecting unit, and a physiological signal transformation module, wherein the physiological signal transformation module is coupled with the audio input unit and the physiological signal detecting module, and transforms the physiological signals received from the physiological signal detecting module into corresponding physiological audio signals. Then, the smartphone receives the physiological audio signals, for computing physiological signal detecting results. Besides, the smartphone is coupled with the physiological signal detecting module, for controlling the execution of the physiological signal detecting process.
