A method and apparatus for high-speed rail, Automatic grinding system for rail maintenance on power cars and metro lines, include a polishing device, the polishing device comprises a mounting plate, amounting base for adjusting the cylinder and the grinding mechanism, A left and right end of that mounting plate are symmetrically mount with mounting bases, A regulating cylinder is installed in themounting base, the adjusting cylinder is two-way telescopic structure, A grinding mechanism is installed at the front and rear ends of the adjusting cylinder, The grinding mechanism comprises a workframe, a No. 1 fixed plate, a No. 2 fixed plate, a rotating shaft, a rotating grinding wheel, a rotating gear, a transition gear, a rotating electric machine, a fixed seat, an adjusting electric pushrod, an adjusting frame, a No. 1 working plate, a No. 2 working plate, a rotating shaft, a rotating grinding wheel, a rotating gear, a connecting gear, a rotating electric machine, an auxiliary springand a guide plate. The invention can solve the problems of high labor cost, low working efficiency, inconvenient adjustment, small use range and the like existing in the existing rail maintenance andpolishing process, and can realize the function of automatic polishing of the rail.