The invention discloses a grating type distortion coefficient measurement device of an automobile profile measurement system. The objective is to solve the problem of camera distortion coefficient measurement of an automobile profile measurement system. The measurement device is mainly formed by a square steel frame (1), a grating ruler (2), a V-type clamp groove (3), a steel filament (4) and a guide rail base plate (6). The V-type clamp groove (3) is adjusted to control stretching of the steel filament (4), the image of the steel filament in a distortion image is changed into the original straight line, and the distortion coefficient can be obtained according to the displacement of the V-type clamp groove (3). The measurement device is simple in structure, high in detection precision, simple to operate, easy to install, quite low in cost and reliable in performance.