A method to measure the three-dimensional (3D) surface figure based on three step phase-shifting is proposed. Firstly, the grating projected by a projector is pre-corrected to assure standard sinusoidal fringe projected on the reference surface. Secondly, three frames of grating with same phase-shifting are projected on the surface of the tested object by a projector during measurement. Three frames of deformation fringe patterns are captured by a CCD camera and the phase is extracted from a phase calculation model. Finally, the 3D surface figure of the tested object can be reconstructed by height mapping formula. The method has stronger anti-noise ability, measurement process can still be performed in large noise environment, which lay a foundation for dynamic on-line measurement. The feasibility of this method is verified by simulations and initial experiments.