A projection profilometry by two-step generalized phase-shifting is proposed after the two-step generalized phase-shifting algorithm is introduced into the three-dimensional (3D) shape measurement.Firstly,two phase-shifted randomly sinusoidal fringe patterns are projected onto the tested object by a digital-light-processing (DLP) projector.The fringe patterns modulated with the object′s surface are captured by a CCD camera.Secondly,the background component is eliminated from deformed gratings by averaging method pixel by pixe l after the appropriate window size is chosen,and the phase step between two phase-shifted randomly sinusoidal fringe patterns is determined by subpixel interpolation,extremma of the fringe and multi-point average method.Then,the phase is extracted from the defromed patterns without the respective backgrounds by the step value.Finally,the experimental evaluation is conducted t o prove the validity and performance of the proposed method.The experimental result is analyzed and compared with that of other methods.The effectiveness and superiority of the proposed method are also demonstrated.