Abstract: Due to the limitation of geological conditions and engineering conditions, some roadways in coal mine can not avoid unstable rock formations and need to be constructed in unstable rock formations. In this paper, under the conditions of large deformation of roadway, long time of bottom dropsy and mine pressure, the soft and broken position of rock surrounding a mine substation is discovered. It is proposed to use grouting anchor to reinforce unstable surrounding rock with anti-suspension arch to control the bottom dropsy, improve the overall bearing capacity of roadway surrounding rock, ensure the effect of chamber support, and reduce the maintenance cost in the later period of chamber.