The invention belongs to the technical field of honing, and discloses a scale plate structure of a vertical honing machine. The scale plate structure comprises an upper installing base and a lower installing base. A scale plate is installed between the upper installing base and the lower installing base. A scale layer is arranged on the surface of the scale plate. The scale plate is in sliding fit with a measuring head integrated with a cross arm. The measuring head comprises a frame. The interior of the frame is an inner cavity for the scale plate to penetrate. At least one side wall of the frame is provided with a through hole. Springs are arranged in the through holes. One ends of the springs are connected with sliding tables arranged in the inner cavity, and the other ends of the springs are connected with touch plates outside the frame. The sliding tables are in a ball coronary shape, and the ball coronary faces of the sliding tables make contact with the surface of the scale plate. According to the scheme, the inner cavity of the frame is provided with the sliding tables in the ball coronary shape, the ball coronary faces of the sliding tables make contact with the surface of the scale plate, and when the frame moves on the scale plate to a concave and convex position on the surface of the scale plate, the frame easily slides across the concave and convex position through the ball coronary faces of the sliding tables, and the situation that the measuring head and the scale plate are clamped is prevented; and the cross arm integrated with the measuring head can move very smoothly.