A generalized mathematical model of human body current threshold for perception was established and the current flowing through human body could be arbitrary cyclical waveforms. The relationship between human body current threshold for perception and current frequency, true root mean square (RMS) value and influence factor was described. A test system was established based on electroencephalogram (EEG) to study the relationship between human body current threshold for perception and current waveform, frequency and duty cycle so that the data could be obtained objectively and reliably. At least 850 groups of current threshold for perception and 16-lead EEGs were acquired. The theoretical analysis are verified by experimental data, and an amendment proposal on leakage current evaluation limits specified in International Electro-Technical Commission (IEC) standards is suggested.