To evaluate wheel defect, it is necessary to develop a new NDT on railway wheel. Unlikely a conventional NDT system, the NDT system of the present paper can detect a sub-surface crack. In the present paper, the new NDT method is applied to the detection of surface and sub-surface crack defects for railway wheels. To detect the defects for railway wheels, the sensor for new NDT is optimized and the tests are carried out with respect to sub-surface defects respectively. The result shows that the surface crack as well as sub-surface crack could be detected by using new NDT method.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.