Abstract: In this paper, we study the impulse response of thickness vibration of disc transducer.using mechanoelectronic equivalent circuit, Kirchoff's Iaw and courier's transformation.The formulas of admittance, transfer function and impulse response of thickness vibrating disc are obtained.By taking computation on HP-1000 computer with different backing and matching layers for ZNL-2 piezoelectric ceramic disc, we obtained the admittance transfer function and impulse response at such cases. At the same time, we study the idea, put forward by H.W.Person and C .H.Hertz, that the transducer is of Gaussian shape's transfer function, its impulse response is the best. When the impedance of matching layer is 4, 6(1e+6)kg/m²·s), the backing layer's 7.5,15.5(1e+6)kg/m²·s), and the thickness of matching layer 1.12λ/4, the impulse response is better, and H. W .Person and C .H.Hertz's idea is right.We measured some admittance of thickness vibrating disc transducers ultilizing HP-impedance analyser and 3033 X-Y recorder, so do the impulse response by impulse response measuring apparatus.The experimental result is agree with the theory, these result can be refered to in process of manufacturing in factory.