Abstract: A medical device with real-time physiological signal analysis function is disclosed. An ECG signal is generated by detection of detection circuit to the human heart while conversion circuit receives the ECG signal and converts it into an ECG data. The ECG data is sent to a process control unit for being processed to generate a HRV parameter. The ECG data and the HRV parameter are shown by a display unit for real-time analysis of changes of HRV in time domain and frequency domain. Thus doctors can make diagnosis according to these data. Moreover, The process control unit is coupled to the memory module so as to save the ECG data and the HRV parameter. Thus after long-term data collection of the ECG and HRV, doctors can make diagnosis by means of these data.