Abstract: In view of the large area collapse of the coal wall in the triangle area during the mining process of 3210 isolated island face in Wangpo coal mine, the influence range of the leading bearing stress and the failure depth of the coal wall in the isolated island face are analyzed, field measurement and industrial test, and the failure mechanism of the triangle coal at the end is expounded. In order to provide a basis for the selection of reasonable grouting area and grouting parameters for the prevention and control of triangular coal caving, grt-101 chemical grouting material is proposed to reinforce triangular coal and its surrounding rock. Based on this, industrial tests are carried out in 3210 isolated island working face, and good results are achieved.