The invention discloses a grinding machine for a brake valve of a railway vehicle. The grinding machine is characterized in that the whole machine is composed of a main machine body, a workbench, a valve grinding station, shields, a plane grinding station for the upper surface of a slide valve and a plane grinding station for the lower surface of the slide valve; the three stations are composed ofreciprocating motion mechanisms, pressing mechanisms and power transmission mechanisms respectively; each reciprocating motion mechanism is composed of linear guiding rails, a connecting board and agrinding air cylinder which are installed on the workbench, a first sliding board installed on the linear guiding rails, a second crooked board installed on the first sliding board and a hinge pin, anadjustment spring, a pull rod, a drum-shaped hinge pin and combined oil stones which are at the front end of the second crooked board; each pressing mechanism is composed of a second sliding board and a pressing air cylinder base, a pressing air cylinder, a pressing rod support, a pressing rod, a bearing, a reset spring and a reset board which are located on the second sliding board; each power transmission mechanism is composed of a first crooked board, an oscillating rod, first meets and a second meet. The grinding machine is ideal equipment for grinding the brake valve of the railway vehicle.