The invention discloses a belt scale, and the belt scale is disposed on a conveying rack. The conveying rack is provided with a rotating belt, wherein the upper part of the rotating belt moves from the right to the left, and the lower part of the rotating belt moves from the left to the right. The belt scale comprises a scale frame, a through shaft disposed on the conveying rack, and a plurality of carrying rollers which are sequentially arranged and are used for supporting the belt. The scale frame is located below all carrying rollers, and the right end of the scale frame is connected with the through shaft. The through shaft is rotatingly connected with the conveying rack, and the left end of the scale frame is provided with a weight sensor. The weight sensor makes contact with the upper surface of a first fixed longitudinal beam on the conveying rack. The belt scale is high in weighing accuracy.