The invention discloses a bottom-blowing water-cooling film-blowing device. The bottom-blowing water-cooling film-blowing device mainly comprises a plastifying mechanism, a film-blowing mechanism, a rack, a cooling mechanism, a cutting mechanism, a traction mechanism and a rolling mechanism, wherein the plastifying mechanism, the cutting mechanism and the rolling mechanism are positioned on ground; the film-blowing mechanism is positioned on the rack; and the cooling mechanism and the traction mechanism are positioned in water slots below ground. After being molten and plastified through the plastifying mechanism, materials enter the film-blowing mechanism at the left side, the film-blowing mechanism blows the materials into a film, and the film enters the cooling mechanism below for beingcooled. The cutting mechanism cuts when the film enters the cooling mechanism. The cooled film is guided by the traction mechanism and is finally rolled by the rolling mechanism. The bottom-blowing water-cooling film-blowing device disclosed by the invention is suitable for producing ultra-wide films with large fold diameters. Water in the water slots can keep a constant-temperature state throughcirculation of a water pump. A film tube is downwards pulled, so that self-weight breakage of the film is greatly improved. The performance of the shaped film is greatly improved in comparison with the performance of the film produced by a conventional process.