A novel surface measurement system has been developed in order to evaluate the process of fabricating micro lenses. White light interferometer is conventionally applied for the flat surface and spherical surface of lens mold. However it is difficult to evaluate the non-spherical lens mold by using the white light interferometer. We propose light scattering method which applied the extended TIS model in order to evaluate a surface texture of a non-spherical microlens mold. In this report we describe the experiment result which measure the surface roughness of flat Si wafer coated with Cu. The developed system can detect scattered light pattern from the surface, and the roughness is agreed with of TIS.