The invention relates to a stretch plastic geogrid automatic winding and unwinding machine and a using method thereof. The machine comprises a fixed rack, an air expansion shaft and a rotating mechanism, wherein one end of the air expansion shaft is in shaft connection with the rack, and the rotating mechanism drives the air expansion shaft to rotate. The machine further comprises an unwinding mechanism and a movable supporting device, the movable supporting device is slidably connected to the rack in the radial direction of the air expansion shaft, and a supporting part is slidably arranged on the movable supporting device in the axial direction of the air expansion shaft. The other end of the air expansion shaft is in shaft connection with the supporting part. The unwinding mechanism comprises a movable box body which is slidably connected to the rack, a grating roll pushing plate fixedly connected to the movable box body, and a walking device for driving the movable box body to movein the axial direction of the air expansion shaft. The grating roll pushing plate is arranged on the side, away from the supporting part, of a grating roll. According to the machine, the labor intensity of winding workers can be reduced, the labor cost of an enterprise can be reduced, the length of a clamped grating in the original winding process can be shortened, the production cost can be reduced, the phenomenon that the end face of the grating roll is not orderly is eliminated, construction is facilitated, the construction cost can be reduced, and the construction efficiency is improved.