Abstract: Backfill mining serves as an effective method of load reduction and impact reduction in impact pressure mines, but the support-surrounding rock relationship of the fill face is significantly different from that of the conventional face. In order to optimize the support selection for the filling face, improve the effect of surrounding rock control and reduce the cost of equipment, the 1123 working face of GuCheng coal mine was used as the engineering background to study the characteristics of roof load distribution and analyze the relationship of support- surrounding rock coupling under the condition of filling mining in impact pressure mines. The results show that: there are obvious differences in the shape of the time sequence curve of the support load between the filling stage and the mining stage, the former curve is smooth and has a small slope, while the latter has frequent transient phenomena and a large slope; there is no obvious periodic change in the support load under the support of the filling body, which indicates that the movement mode of the hard top plate changes from the periodic rupture type to the continuous subsidence type; there is an increasement in the support load time-sequence curve under the influence of the mining effect, the thick top coal, the distance from the front end of the top beam to the coal wall, the filling rate and other factors, and there is an increasement in the support load time-sequence curve. Under the influence of mining dynamic effect, thick top coal, the distance from the front end of the top beam to the coal wall, filling rate and other factors, the time sequence curve of support load exists increasing resistance type, constant resistance type and decreasing resistance type, but the rapid decreasing resistance type is dominant, which indicates that the initial supporting force of bracing in the 1123 working face is too large as 24 MPa, resulting in the second breakage of the thick top coal; the gob is divided into non-sufficiently compaction area and sufficiently compacted area, and the model of the continuous subsidence of the hard top plate under the effect of the support of the filling body is constructed, and the influence of the filling rate on the shape of the subsidence curve is obtained. Considering the damage of thick top coal, the method of determining the resistance of the supports in the filling face is proposed, the reason for the occurrence of rapid reduce resistance in the support load curve is explained and the optimization principle of the support stiffness and the initial support force is given, which improves the support-surrounding rock coupling relationship and enhances the effect of thick top coal and hard roof control.