Abstract: The influence factor of crack of inclined thick seam and top coal caving and drawing characteristics were analyzed in the paper.On the practice basis of fully mechanized sublevel caving of hard and thick coal,a discrete element software was used to do simulation test and influence of crack in process of mining coal on the top-coal caving and the development process of the fracture were analyzed,which could be used to determine the top coal caving characteristics.The result of the simulation experiment showed that the size of crack distribution and developed shape are the most important influence factors on top coal caving and drawing characteristics,and the more cracks,the greater the length,the smaller of the spacing,the more developed stratification,the better the top coal caving and drawing characteristics.Fully mechanized coal production should be evaluated according to the topcoal caving property in some extent.