On the basis of the geological and mining conditions of a mine in Datong,a comprehensive research method combining the theory of mining subsidence,the surface movement observation on spot and the numerical simulation was adopted to investigate the subsidence reduction and protection problems of the coal seam group mining under the high voltage power lines.The research conclusions are:designed the exploring roadways is parallel to high-voltage lines,making the high-voltage line in the roadways coal pillar midline and mining working face vertical to the exploring roadways,so as to faver good protection;the criterion of line tightening and tensile failure was proposed,the critical value of tower tilting is at least 2 times larger than the power standard;the filling material of waste rock type for reducing subsidence was developed,the subsidence reducing effect of the test materials No.5 after filling under single coal seam mining reached 68.7％;the simulated subsidence reduction results of the combined mining scheme of coal seam group show that the No.2 and No.3 can realize the safe mining under the high voltage line.The research results in this paper can provide the correct development direction and scientific decision basis for the future studies of the protection to the ground power supply circuit and its regulations for implementation.