Abstract: The photoluminescence (PL) technology was used to identify the crystal orientation of the polycrystalline silicon wafer, the elastic modulus of polycrystalline silicon wafer in different orientations was measured through the nano-indentation experiment. The finite element program was used to establish the polycrystalline silicon wafer finite element model containing the information of grain size and grain orientation, and then the elastic modulus got from the nano-indentation experiment were inputted to the model to obtain the bending strength of polycrystalline silicon wafer with different grain sizes and grain orientation distributions; the simulation results were verified by three-point bending experiment. The results show that elastic modulus and hardness of polycrystalline silicon wafter in different grain orientation distributions are different. The maximum bending stress value and the maximum stress position of the polycrystalline silicon wafer are affected by crystal orientation distribution. Grain shapes will affect the maximum bending stress. Reducing the grain size can reduce the maximum bending stress.The model's correction is verified by the three-point bending experiment.