In order to explore the factors influencing the particle flow rate, the indoor pepper pot experiment was combined with PFC2D and 3D. The results show that the particle mass flow rate is positively correlated with the vessel aperture in a certain range, and meets Beverloo formula, and the particle flow rate has a negative correlation with the particle diameter, particle stiffness, friction coefficient and other parameters. In addition, the inclination angle and external force at the opening also have important influence on the particle movement. Increasing the inclination angle can change the flow state of the particles from funnel to horizontal push flow, and increase the flow rate. The external force can destroy the arching structure formed between the particles and reduce the probability of blockage.