This invention discloses a system and method for extracting VF signal in ECG recorded during uninterrupted CPR. The method and system applies an adaptive algorithm incorporating the EMD and least mean square (LMS) filtering to effectively model the CPR artifacts such as chest compression signals. Thus, A VF signal in ECG recorded during uninterrupted CPR can be extracted without deteriorating the reliability of the waveform parameter (i.e. AMSA) of shockability. The present invention enables uninterrupted CPR performed during recording ECG for accessing the shockability, so that an increase the probability of successful resuscitation is achieved.