The problem of phase unwrapping is widespread in fringe projection profilometry. In this paper, a phase-shift coding unwrapping method is proposed. This method uses the multi-step phase-shift method to solve a phase and embeds the code of the mark fringe series into the phase-shift amount in an additional coded image. When decoding, one can solve the coded phase-shift amount at the point and thus obtain the absolute phase by analyzing the light intensity information sequence of different phase shifts at each pixel point. This method requires only a few images and can unwrap point by point. It is suitable for the shape measurement of a discontinuous object but it is easily affected by the noise of the projector and the camera. By adding the complementary coded fringe images, we propose an improved phase-shift coding unwrapping method, which can not only be used for the shape measurement of discontinuous objects but also significantly enhance the noise robustness. The simulation analysis and experiment confirm the effectiveness of the proposed phase-shift coding unwrapping method.