Abstract: To further study and understand the strata behaviors of "three soft" coal seam in mining process, taking Linnancang Mine as the engineering example, we use staggered roadway arrangement to carry out optimization, and analyze and study the plastic damage area forming in mining proces by the method of combining numerical simulation and actual situation. The analysis shows that there will be a mining "O" ring below key strata with the advancing of the working face, and with the increase of continuous surface, the plastic damage area will present a "continuous arch”.