Research conclusions:The study shows the boundary angle should be used for calculating the safety distance for high －speed railway and the passenger dedicated line of ballastless track，and the rock displacement angle should be used for calculating the safety distance for normal speed railway． Moreover，combined with engineering examples，the method and way for the railway alignment in goaf are presented，including the comparison and selection of the railway alignments in the periphery of mining area，local optimization of alignment in the mining area and the railway alignment based on calculation and monitoring of the deformation of goal ．