The invention relates to a grinding method for a sliding block groove surface. A sliding groove is formed in the upper end of a sliding block, and to-be-ground grooves are formed in the left and rightsides of the interior of the sliding groove. Grinding of the two grooves in the left and right sides comprises the following steps that S1, the to-be-ground sliding block is fixed to a conveying platform and moves front and back along with the conveying platform; and S2, two grinding wheels on the left and right sides are selected, the two grinding wheels on the left and right sides are arrangedin a left-and-right inclined shape and are arranged in a front-and-back staggered manner, and grinding curve faces for grinding the grooves are formed on the edges of the grinding wheels, the grindingcurve face of the grinding wheel on the right side grinds the groove in the left side, the grinding curve face of the grinding wheel on the left side grinds the groove in the right side, the conveying platform drives the to-be-ground sliding block to move towards the two grinding wheels, and the two grinding wheels keep high-speed rotation to complete grinding of two right-angled faces in the sliding groove. Abrasion of a grinding tool in the grinding process of the sliding block can be reduced, the output efficiency of the finished sliding block is improved, the grinding process is simplified, and the accuracy of the grooves of the sliding block is improved.