In order to reduce the noise points when measure the shape of 3D object using Phase Shift Profilometry (PSP) methods, in this paper we propose a novel Three Wave Length PSP (TWPSP) method. Firstly, the direct problems of equivalent wavelength and unwrapped phase are analyzed. Then, the solution of unwrapping method for TWPSP is derived. Finally, based on the global phase filtering the phase noises are reduced. We simulated and compared the proposed TWPSP and the classical TWPSP. Experiential results shown that the noises are greatly restrained. Since the proposed method does not need to calculate the equivalent phase maps, the implement is improved than the classical TWPSP.