Abstract: The invention generates synthetic composite waveforms for determining an individual's physiological state, and includes steps of: obtaining a periodic physiological signal of an individual within a time frame; analyzing the periodic physiological signal to obtain and to convert peak-to-peak time intervals of the periodic physiological signal into frequencies; establishing a physiological variation waveform according to the variation of the frequencies; defining at least one synthetic basic waveform according to the frequency trend or fluctuation amplitude of the physiological variation waveform; combining at least two synthetic basic waveforms to generate at least one synthetic composite waveform; and defining respectively each of the at least one synthetic composite waveform as a physiological state.