Abstract: With the discrete element method(DEM) which is able not only to model displacing between particles but also to analyze dynamically the force transmission relation among particles. The latter is a special performance of discrete element method. Based on DEM, a program is developed. The paper calculated and simulated some effect factors of agricultural particle material flowing arch formed in outlet by program. The relationship between the cohesion, friction, size and critical outlet diameter and arch highness are derived. The results of calculation are coordinate with the experimental ones. So , DEM is a useful method and tool for study agri-cultural particle materials.