Abstract: High-entropy alloys have been widely used in many fields due to their excellent properties such as high strength and high hardness that cannot be surpassed by traditional alloys. In this work, the shear mechanical behavior of Al_xCoCrFeNi high-entropy alloys was studied by a molecular dynamics (MD) simulation. The effects of temperature and Al content on the shear modulus and shear strength of Al_xCoCrFeNi high-entropy alloys were specially investigated. The results show that the shear modulus and shear strength decrease gradually with increased temperature, which is ascribed to the fact that the higher temperature, the more prominent thermal vibration between each atom, and the more easily the structure is destabilized. When the temperature is the same, the shear modulus of Al_xCoCrFeNi enhances but the shear strength declines as the Al content increases (x is between 0.5 and 2.0). Moreover, the simulations results show that the higher the Al content, the greater decrease in shear modulus with increasing temperature, while the drop in shear strength is not significant.