In order to obtain the surface gradients in phase measurement deflectometry (PMD), horizontal and vertical phase-shift fringe images need to be obtained respectively, so more images are usually required. In order to reduce the number of fringe patterns, a new phase acquisition method based on composite fringe patterns is proposed, which is realized with five compound oblique fringe patterns by superimposing the horizontal and vertical phase information to form oblique fringes. The phase measurement accuracy is higher than that of the five-step crossed grating phase-shift method. Furthermore, the phase acquisition method is improved to overcome the second-order nonlinear error of the system by using seven compound oblique fringe patterns. Computer simulation and experiments show the feasibility of the proposed method, and its measurement accuracy is higher than that of the crossed fringe method with the same number of frames.