Abstract: The strata behavior laws of the 42104 fully mechanized caving face was simulated experimentally in Qing Gangping coal mine. This research has showed that the first weighting interval of the basic roof was from 64~66m, and the periodic weighting average interval was 27m.The first weighting dynamic load coefficient was 1.27, and the dynamic load coefficient average of the periodic weighting was 1.36, so the pressure integrally belonged to "medium strong".The more pronounced increase area of the first weighting interval in front of the coal wall is 16.75m within reach in front of the coal wall.The dramatic increase area of the periodic weighting interval in front of the coal wall is 45.01m within reach in front of the coal wall.The advanced support distance of fully-mechanized coal caving face should reach 40m range in front of the coal wall.