The invention relates to a method for estimating central artery blood pressure. The method includes extracting a pressure oscillating waveform in a tourniquet, building a generalized transformation function of a central artery to an upper-arm artery blood pressure waveform, generating a central artery pressure waveform according to the pressure oscillating waveform and by using the generalized transformation function, and acquiring a pressure value of the central artery according to the central artery pressure waveform. The invention further relates to a device using the method to estimate the central artery blood pressure.