Abstract: According to the situations that the large mining height working face is easy to appear roof caving, and the roof falling zone will not only cause the empty-support of hydraulic support, but also easy cause gas accumulation, on the basis of the hazard analysis of caving area, a double liquid quick-setting filling material is developed according to the research of working performance of hydraulic support and the specific situation of roof caving of the working face; the material has the properties of rapid hardening, early strength, light weight and constant resistance. The material will achieve defluidization in 2 min after mixing, and the compressive strength can reach 3 MPa in one day. The fast filling technique is used for caving zone filling at working area, which ensures the normal mining at working face.