Cracks in polymer bonded explosives (PBXs) may occur during manufacturing, transportation and storage stages. The surface crack of explosives has an important influence on their mechanical properties and detonation performance. Quantitative detection of the depth of the surface crack is of great significance to the process of surface crack removal. The numerical simulation of surface crack depth estimation was investigated by using Rayleigh surface waves which propagate along the cylindrical and spherical surfaces of PBXs. The propagation patterns of surface waves were studied on these two types of surfaces. The reflection and transmission of surface waves at different frequencies in PBXs with crack of varied depth were simulated through the finite element method (FEM).The FEM results indicate that the depth of crack in curved surfaces can be deduced according to the amplitude variations of reflected and transmitted waves.