For rigid objects moving on-line on the pipeline, the projection composite grating can solve the contradiction between different frequency requirements for pixel matching and phase unwrapping. However, when the phase is calculated, it is necessary to filter the composite grating, which will reduce the reconstruction accuracy. Based on Stoilov algorithm, an on-line three-dimensional(3D) measurement method of composite grating projection without filtering is proposed. By the design of the composite fringe, the phase shift direction of the low-frequency fringe is parallel to the moving direction of the measured object, and the motion of the measured object after pixel matching is converted into the phase shift of the low-frequency fringe. The phase shift direction of the high-frequency fringe is perpendicular to the moving direction of the measured object, and the light intensity distribution of the high-frequency fringe in each frame deformed fringe pattern after pixel matching is exactly the same. Therefore, the phase calculation can be performed directly, and the loss of accuracy is avoided due to filtering. Meanwhile, the intensity of the high-frequency fringe in the composite grating is much lower than that of the low-frequency component, so the high-frequency fringe can be regarded as a weak background light. The accuracy of on-line 3D measurement is guaranteed. Simulations and experiments prove the proposed method’s validity.