The invention relates to a fixing device, and particularly relates to a transformable type fixing device for a solar panel rear film. The fixing device comprises a base, a fixing base, a hydraulic rod, a pressing plate, base plates, fixing blocks, grooves, convex teeth and a solar panel, wherein the lower end of the fixing base is fixedly connected with the pressing plate through the hydraulic rod; the convex teeth are respectively arranged at the two ends of the pressing plate; the base plates are arranged at the two ends of the solar panel; the solar panel is arranged at the upper end of the base; the fixing blocks are respectively attached to the outer sides of the base plates; grooves are formed in the upper ends of the base plates, and are matched with the convex teeth; the convex teeth are welded at the bottom ends of the positioning blocks; the top ends of the positioning blocks are respectively in fixed connection with the two ends of the pressing plate through bolts; reinforcing ribs are arranged between the convex teeth and the positioning blocks; rubber sleeves are sleeved between the positioning blocks and the pressing plate. According to the fixing device, when the convex teeth of the fixing device are damaged, only the convex teeth are required to be replaced and the whole pressing plate is not required to the replaced, so that the cost is saved and the effect is improved.