The shear performance of heterogeneous concrete is very important. In this paper, the parallel bonding model of particle discrete element was used to simulate the direct shear test process of concrete to reveal the shear characteristic and failure mechanism of concrete. The impacts of meso parameters, such as contact modulus, contact stiffness ratio, particle friction coefficient, tensile strength, ratio of cohesive strength to tensile strength, and contact friction angle, on the results of concrete direct shear test results were studied by controlling the variable parameters. The shear deformation resistance of specimen has a significant linear relationship with the contact elastic modulus. The contact stiffness ratio has little impact on the shear test results. Particle friction coefficient, contact tensile strength, ratio between cohesion strength and tensile strength, and contact friction angle have a significant effect on the shear strength parameters. Contact tensile strength, ratio between cohesion strength and tensile strength, and contact friction angle could affact the curve form after peak of shear stress vs. horizontal displacement. This paper provided a reference for particle discrete element simulation of direct shear test of concrete specimens.