Abstract: The research investigates the distribution of the static and dynamic pressures of granular coal, while charging and discharging, on the wall of a special silo with a trouser- shape funnel built in Shanxi province by a particle flow code. The simulation results are compared with those obtained by national code GB50077-2003 and ISO methods. The results show that computational methods of the normal pressure and tangential force offered by present national code and ISO are not entirely suited for the situation of this coal silo; that the static pressure on the upper straight coal silo wall can be computed with the ISO method, but the static pressure upon the lower funnel wall should adopt simulation values; that the dynamic pressure on the upper straight coal silo wall can be computed with the national code GB50077-2003 method, but the friction upon it should adopt simulation values; and that both the dynamic normal pressure and tangential force on the trouser leg-shape funnel need to adopt dynamic simulation values.