Abstract: Roof-contacted filling is an important process of fill mining technology, its effect is related to the safety and recovery rate of ore mining.In order to solve the problem of low roof-contact rate in filling mine, this paper puts forward the active roof-contacted technology of filling body.Through the experimental study, the filling body volume can be increased by adding the matching self expanding material in the filling slurry, and the filling body can be connected to the roof actively by using its self expanding function.Based on the experimental study of the flow performance and the strength of the self expanding filling slurry, and the analysis of the microstructure of the filling by SEM, the best technical parameters of the roof-contacted filling in a lead zinc mine in Guangdong province are determined.When the filling concentration is 73%, the ratio of lime to sand is 1∶4, and the amount of expansion material is 3%, the volume expansion rate of the filling body is 22%-23%, and the strength of the filling body is about 2.0 MPa, which meets the requirements of the top filling technology.