Abstract: To solve the problems of poor lithology and others at the roof and floor of the coal seam in the No.52 mining area of Pulongwan Coal Mine,interval paste filling coal mining technology is adopted.The roof and goaf are supported by using filling bodies,the movement of the rock strata can be effectively controlled.After analysis,the 5211 working face implements a layered filling and downward mining method,with both upper and lower layers having a height of 4.0 m.Based on the in-depth research on the overall layout of the 5211 working face,according to the factors such as geological conditions,mining technology requirements and so on,the working face is determined to be divided into four sections for implementing mining operations.The width of the branch roadway is proposed to be 4.0 m,and the length of the branch roadway is controlled within 100.0 m.In the process design of the branch roadway mining,the "mining 1 leaving 3" mining mode is adopted,combined with the "grouping round" operation mode for branch roadway mining.The theoretical analysis concludes that the uniaxial compressive strength of laboratory filling body materials is not less than 3.98 MPa,and the optimal ratio is a mass ratio of fly ash,cement,coal gangue,and water of 1:1.3:8:2.7,with a mass concentration of 79%.The research results can protect ground buildings and water bodies,and achieve sustainable development of mining areas.