In this paper, we purpose to assess the crack and deterioration level of composed stones in Angkor Monument, Cambodia, by an elastic wave test. The degree of deterioration and crack is generally examined by supersonic wave test, electromagnetic wave test and hardness test. However, the above general methods are difficult to be applied to the stones in Angkor Monument, because there are some problems such as damages on the surface relief and an accuracy of the test results which highly depend on the surface deterioration level. Therefore, in this paper, we suggest the method of an elastic wave test by slightly knocking on the stones. Then, we analyze the elastic wave’s profile, such as velocity, amplitude ratio and frequency etc. From the results, we examine about the relationship between the elastic wave profile and existence of crack or deterioration level of stone. The above examinations are applied to assess the structural safety of composed stones in Angkor Monument.