The process and characteristics of pulverized coal discharge from a visualized plexiglass hopper were investigated. The discharge of coal was difficult due to its small particle size and large specific surface area with strong agglomeration and poor flowability. The addition of gas could improve the flowability of coal as well as increase discharge rate

however excess aeration would decrease discharge rate. The features of pressure distribution were revealed by analyzing the pressure signals from hopper wall during discharge

and overpressure phenomenon was analyzed and pressure transition surface was defined. The quality of discharge such as reduction of overpressure，extension of loose area of coal and increase of height of transition surface could be improved by aeration to some extent. In addition

gas penetration occurred during aerated discharge. Increase of gas flow rate increased the critical height of gas penetration and discharge rate of coal decreased after gas penetration.