The invention discloses a safety type grinding machine used for machining auto part moulds. The safety type grinding machine comprises a bottom plate, wherein two sliding rods are arranged at the leftend and the right end of the upper surface of the bottom plate in parallel, the front ends and the rear ends of the two sliding rods are fixed to the upper surface of the bottom plate through fixingframes, the side surfaces of the two sliding rods are slidably connected with sliding holes in two first fixing blocks correspondingly, and the upper surfaces of the two first fixing blocks are fixedly connected with the lower surface of an upper plate. Cooling fluid which is used enters a water holding tank through a filter screen plate, and the cooling fluid in the water holding tank enters a water tank through a filter box, so that the using efficiency of the cooling liquid is improved. A fixing device and a second fixing plate can fix the auto part moulds of different sizes, so that the applicability of the safety type grinding machine for the auto part moulds is improved. An arc-shaped cover prevents the cooling liquid or grinding debris from splashing to ensure the safety of workers.The workers can conveniently observe the polishing effect of the auto part moulds under the condition of dark light through a lighting lamp.