Abstract: The fracture movement of rock layers caused by coal seam mining has led to a series of mining damage and environmental problems. In recent years, grouting and filling of overburden separation layer has been more and more applied to release of " under-three" pressed coal. In order to systematically introduce the test results of grouting and filling in overburden separation layer, this paper makes a statistical analysis on the effect of subsidence reduction test by grouting and filling in separation layer in recent 40 years. This paper explores the influence of geological factors, mining factors, and construction factors on the grouting filling of overlying strata separation, analyzes the factors that restrict the promotion and application of overlying strata separation grouting, introduces the new progress of current overlying strata separation grouting technology in grouting theory, grouting equipment, drilling construction, and grouting technology, and explains it in conjunction with the grouting filling case of overlying strata separation in the 3117 working face of Xiadian Coal Mine, Lu'an Group. The results show that the grouting and filling of overburden separation layer can not be simply homogenized in the application process, and geological factors are the primary conditions for the application of grouting and filling of overburden separation layer; mining factors have an important influence on the formation of separation space; grouting technology has a direct impact on the settlement reduction effect and economic benefits of grouting engineering.