Abstract: The accumulation layer landslide mainly composed of the slope deposits of the fourth system collapse is currently the most common type of landslide. The movement characteristic of after instability such as movement velocity and accumulation range are two important indicators for evaluating its hazard. The particle discrete element PFC^3D has obvious advantages in simulating the instability, sliding and accumulation of this type of landslide, however, some problems such as too many mesoscopic parameters which are difficult to select reasonably still exist. So, an in-depth study has been carried out on them. Firstly, taking Shidaguan accumulation layer landslide as an example, the unstable movement process is reproduced with PFC^3D, and compared with the on-site investigation results to validate the numerical model. Then, with this model, the influence of the friction coefficient of the sliding surface, local damping and viscous damping on the movement distance and accumulation range of the sliding body is mainly discussed. The increase of the friction coefficient of the sliding surface reduces the sliding speed and movement distance of the sliding body, and decreases the range of the accumulation body. However, the degree of influence decreases with the increase of the friction coefficient. The increase in the volume of the sliding body will lead to an increase in the accumulation range and the maximum movement distance. The increase of local damping will cause greater hindrance to the movement of particles, reducing the sliding speed and the degree of damage. The influence degree of viscous damping on the particle motion decreases with the increase of the damping coefficient. The increase of normal viscous damping will increase the particle velocity without affecting the motion distance, while the increase of tangential viscous damping will simultaneously reduce the particle velocity and the motion distance. When conducting landslide simulation with PFC^3D, reasonable friction and damping coefficients should be set simultaneously based on the duration of the actual landslide occurrence, the accumulation range of the landslide mass, the average velocity and the displacement value. The research results can provide useful references for the simulation of the unstable motion range of similar landslides.