Deformed fringes often contain fundamental frequency information degraded by background intensity information in structured light projection of three-dimensional (3D) surface shape measurement of complex tested object.The background intensity information needs to be removed in order to avoid frequency aliasing,get fundamental frequency component and enhance measurement accuracy and range in Fourier tansform profilometry (FTP).An improved FTP is proposed to eliminate the zero frequency component.Firstly,two phase-shifted randomly sinusoidal fringe patterns are projected onto the tested object by digital-light-processing (DLP) projector.The fringe pattern modulated by the object′s surface is captured by a CCD camera.Secondly,the difference of tw o fringes is obtained after numerical processing.The standard fast Fourier transform (FFT) is applied to fringe difference.Thus the simple filter can be designed to extract the fundamental frequency without zero component in spectral domain.A simple fringe pattern projection can be accomplished if the proposed method is combined with the color or composite grating.Finally,facial mask is used for specimen,and the experimental evaluation is conducted to prove the validity and performance of the method.The experimental results are analyzed and compared with those of the traditional method.The effectiveness and superiority of the proposed method are demonstrated.