The detection of the consistency of the piezoelectric transducer needs an admittance circle measuring instrument. The new generation of digital piezoelectric transducer admittance circle measurement system based on the ARM7 controller and high speed ADC is given. The sinusoidal signals of different frequencies are generated with the control of ARM7, the two way original measured waveforms are captured by high speed ADC simultaneously, and the phase difference and amplitude ratio of the original waveforms are processed by the digital signal processing method, then the admittance circle can be obtained. Comparing with the analog admittance circle, the piezoelectric transducer admittance circle measurement instrument based on ARM controller can eliminate the influence of the low frequency filter and can effectively measure the low frequency region. The experimental results show that, compared with capture card based admittance circle measuring instrument and 4294A, the accuracy of ARM7 based admittance circle measurement instrument has improved to some extent comparing with the capture card based admittance circle measurement instrument and 4294A measured results.