Abstract: Ultrasonic non-destructive testing result is correlative with ultrasonic transducer sound field characteristic, and numerical method can effectively analyze ultrasonic sound field characteristics. Finite difference time-domain method(FDTD) is used to analyses 2D fluid kinetic equation, FDTD model is described. Perfect matched layer method is used to achieve boundary condition and obtain desired absorbing effect. Ultrasonic sound field propagation and disc sound source characteristic is researched through numerical calculation and simulation, effectiveness and feasibility of the algorithm is confirmed in comparison with other research results. Numerical simulation and practical measurement test is accomplished in focal ultrasonic transducer with pulse stimulated. There is good consistency existing in experiment result of sound field characteristic in axial cross section.

Key words: Perfect matched layer, Ultrasonic sound field, Finite difference time domain method