The invention relates to a water spraying device for cooling a thin film. The water spraying device is used for cooling a thin film casting piece in the forming process of the thin film casting piece,so that the crystallinity and the grain thickness of the thin film casting piece are consistent. The water spraying device comprises a water tank, a swing frame and three parallel water spraying pipes on the swing frame, wherein the swing frame comprises a water inlet side end plate, a rotating side end plate, a pull rod and a rotating shaft; the rotating shaft is mounted on a side plate of the water tank through a self-lubricating sleeve; a swing frame swing angle adjusting device is mounted on the swing frame; each water spraying pipe comprises a round pipe arranged on one side of a chilling roller in parallel and a rotating handle; a long seam with the width being the same as that of the roller face of each chilling roller is formed in each round pipe; the spraying angle of each waterspraying pipe is fixed through a locking butterfly nut; one end of each water spraying pipe penetrates a water inlet side installation plate to be connected with an elbow; and three water inlet hard pipes communicate with the elbow. The water spraying device sprays water evenly and stably, the problem that pits are formed in the surface of the thin film due to uneven water spraying is solved, thespraying distance and angle are convenient to adjust, and the thin film has a good cooling effect.