A Boundary Element Method (BEM) is one of the most frequently used techniques for numerical simulation of ultrasonic nondestructive testing. In simulating a pulse-echo flaw detection test by a BEM, it is desirable that both transmission and reception points of ultrasound are included in the analysis model. However, numerical simulation with that model takes enormous computational time because the scale of the problem is characterized by the distance between these two points compared to the wave length and it is very large in this case. The objective of this study is to develop an efficient numerical method to carry out the simulation which covers the whole process of pulse-echo method concerning mechanical wave propagation. The approach adopted here is to use elastodynamic ray theory in addition to the conventional BEM. In this method, the reflection and propagation of waves in a defect-free region are evaluated by the ray theory and the scattered wave induced by defects by BEM. In this study, the combined method of BEM and ray theory is applied to reflection and scattering problems of 2D time harmonic SH waves in a thick plate model. Both BEM and ray analysis are conducted in the frequency domain and the results obtained are transformed into time-domain solutions when it is needed. Numerical examples show that the combined method can give as accurate solutions as the conventional BEM with less number of boundary elements and the proposed method is very efficient. ©2000 American Institute of Physics.