In this paper, a 10×10 metasurface reflector antenna array based on PIN diodes for beam scanning is designed. The surface of the antenna element of the antenna array is composed of a circular metal patch and four parasitic elements. The current on the antenna element is changed by controlling the working state of the parasitic element, so that the antenna unit theoretically form a phase difference of 180° in different states.In this paper, CST software is used to simulate and analyze the antenna. The operating frequency of the antenna is 15 GHz. The reference phase is added to the beam scanning calculation principle based on discrete amplitude weighting, and the optimization of the pattern reconstruction is carried out. Through the analysis of the simulation results The reference phase that can best restore the pattern is found, which improves the beam scanning capability of the antenna. Since the traditional phased array unit needs to be equipped with a phase shifter, and the antenna unit only needs a diode, its structure is relatively simple, the manufacturing cost is low, and it is suitable for forming a large-scale array. The CST simulation results show that the metasurface antenna has good beam scanning results in the range of ±50° on the ZOX plane.