The vertical optical measurement technique with coaxial projection and imaging optical axis based on the modulation analysis provides a means to solve the problem of shadow and occlusion for measuring the complex surface or step-like surface. Without the phase truncation calculation and phase unwrapping steps, only the modulation information is needed to reconstruct the surface of the tested object in the method, which is widely used as one of the optical three-dimensional measuring techniques. Aiming at the problem of the vertical optical measurement based on the Fourier transform analysis, this paper introduces wavelet transform in modulation measurement profilometry by using partial analysis and multi-resolution characteristics of the wavelet transform for improving the measurement precision based on single fringe analysis at every scanning position. The relationship between the wavelet coefficient and the modulation is deduced, and the computer simulation and the experiment show the validity of the method.