Abstract: In this paper, a gently inclined medium-thick phosphate orebody was taken as the research object, and the pre-controlling roof and sublevel open-stope mining with subsequent filling method was proposed to exploit it.In order to solve the problems in practical production, such as large rate of mining-cut ratio, more complex process for controlling roof stability, and lower production capacity.The method with extraction roadway arranging in orebody was study, and numerical simulation method was used to analyze the stability of surrounding rock in order to obtain the reasonable mining structure parameters.Furthermore, some technologies such as spray anchor net roof support, cemented phosphgypsum backfill, etc., have been comprehensively applied, at last, the safety, efficiency and green mining of resources was realized.The industrial application shows that:the mining structural parameters of sublevel room with height of 16 m, width of 6 m, cutting height under roof of 4 m and mining height in the bottom of 12 m, can guarante the roof stability.Stope production capacity is about 3000 t/d, the dilution rate is about 5%, the recovery rate is about 86%, the rate of mining-cut ratio is 61 m³/kt.This mining method has a better application effect, and provides a reference for similar projects.