A molecules dynamic simulation model was established to simulate the tension of Al₂Cu with voids under the environment of normal temperature and constant engineering strain rate. The influence of void size, quantity and its distribution on the mechanical properties of Al₂Cu was studied by adopting embedded atomic method. The results show that the presence of void causes the appearance of free surface in the model and stress concentration at the inner edge of void, which greatly reduce the tensile strength and deformation ability of the material. In addition, the plastic and tensile strength of Al₂Cu decrease obviously with the increase of void size. The stress-strain curves corresponding to different number of void are basically overlapped in the elastic deformation stage and both the plasticity and tensile strength decrease for more voids. According to the change of void distribution, it can be find that the smaller the angle between the direction of the connection of the voids and the direction of the tensile, the stronger the plasticity and tensile strength of Al₂Cu