Analyze the familiar failures and its elimination of hydraulic system which affect the processing precision of grinding machine. Find out mostly problems of the hydraulic system. Movable platform ‘crawl’; the velocity disaccord of the movable platform moving out and home; the rapidity falls short of theory value when the movable platform moves speediness; when the movable platform is being start-up or stop, it may rush ahead suddenly; the positions’ precision of the movable platform is affected by the three-position directional control valve. The temperature of oil is too high when the machine is working etc. Bring forward the method how to eliminate these failures. These can offer some reference for grinding machine on its design, use, maintenance etc.