Microstructure surface topography is a key aspect of micro-nano measuring research for it has an obvious influence on the performance and quality of micro-nano devices. White light interferometry is a common method of testing surface profiling. A color CCD camera, rather than a black-and-white CCD camera, is utilized to acquire white light interference images, which contain information of RGB channels. Based on acquired color interference images, wavelet transform method is employed to calculate phase value of corresponding channel in each scanning position. Then zero-optical-path-difference positions are accurately determined via a constructed evaluation function and least square method. Surface topography is eventually obtained via linear relationship between the relative height and the zero-optical-path-difference position. The proposed method is verified by simulation and experiment of measuring standard step provided by VLSI Standards Incorporated.