Abstract: This paper investigated the multi-port caving technology to improve the top coal recovery and caving efficiency of the longwall top coal caving(LTCC)in extra-thick seams.The 3D drawing experiments are designed based on the actual geological conditions of Panel 8222 in the Tashan Coal Mine.Results indicated that in the initial drawing stage, the drawing body of single-port caving is roughly in the shape of a funnel with a narrow bottom and a wide upper part.The drawing body of multi-port coal caving is characterized by a wide middle and narrow ends, the coal caving volume shows single-port>double-port>three-port.During the initial drawing stage, the larger the number of openings, the greater the slope of the top coal boundary line; the larger the disturbance range to the top coal; and the higher the lowest point of the top coal boundary line, the more low-level top coal is lost.The lowest point of the top coal boundary is basically at the center of the group of supports.When the advance of the panel is completed, the three caving ports release more medium and low-level top coal above and in front of the supports, the coal caving volume generally shows three ports>double ports>single port.