Abstract: Taking the 6-2116 fully mechanized coal mining face of No.2 shaft of Nalinmiao Coal Mine as the engineering background, in view of problems of large coal consumption and difficult coal transport in abandoned roadway backfilling on coal pillar recovery working faces, a hydraulic coal unloading device of belt conveyor in underground coal mine was designed. The device is composed of support device, redirection device and hydraulic system. It is installed at intersection of main transportation roadway and auxiliary retracement channel. Using hydraulic pump station as power, the coal is unloaded from the belt conveyor by the support device and the redirection device cooperatively,and then the coal is transported to the abandoned roadway. Through the coal unloading device, the raw coal does not need to be lifted into ground and then transported to underground by trackless rubber truck, which improves economic benefit and filling efficiency, and reduces safety risk. Field industrial test results show that when the shearing speed of shearer is 0.8 m/min, the speed of scraper conveyor is 0.4 m/s, the speed level of transfer machine is low, the speed of belt conveyor is 1.0 m/s, and the extension length of support cylinder and redirecting cylinder is 0.7 m, the coal unloading device can realize continuous coal unloading, which meets needs of coal backfilling for the test working face and ensures normal advancement of the coal pillar recovery working face.