The invention relates to a piezoelectric wafer eigenfrequency measurement method. The method comprises the following steps: (1) arranging a measurement device including a function generator, a piezoelectric wafer and a digital oscilloscope; (2) starting the function generator to generate Tone-Burst sine wave signals with a certain period number, conducting electric pulse excitation to the piezoelectric wafer by the function generator at a frequency f, stopping the electric pulse excitation to the piezoelectric wafer when the function generator completes the period number, enabling the piezoelectric wafer to start vibrating freely, and collecting the free vibration signal between two electrodes of the piezoelectric wafer by the digital oscilloscope; (3) adjusting the digital oscilloscope to amplify the free vibration signal between the two electrodes of the piezoelectric wafer in the step (2), and processing the amplified signal by fast Fourier transform; (4) extracting the frequency of the peak on the spectrogram obtained by Fourier transform in the step (3) to obtain the eigenfrequency of the piezoelectric wafer to be tested; and (5) changing the frequency f of the function generator in the step (2), repeating the step (3) and step (4), and measuring each eigenfrequency of the piezoelectric wafer.