Width-adjustable material supporting device and stamping assembly line

The invention relates to the technical field of stamping feeding, and particularly discloses a width-adjustable material supporting device and a stamping assembly line, the width-adjustable material supporting device comprises a first rack, a fixed bracket and a movable bracket, and the first rack supports the fixed bracket and the movable bracket; the fixed bracket comprises a plurality of long-strip-shaped fixed material supporting units, and the multiple fixed material supporting units are arranged in parallel. The movable bracket comprises a plurality of long-strip-shaped movable material supporting units, and the multiple movable material supporting units are arranged on the two sides of the fixed bracket correspondingly. The movable material supporting unit gets close to or away from the fixed bracket through the moving mechanism. The movable material supporting unit is driven by the moving mechanism to move towards the outer side, so that the width of the supporting position is increased, the width of