The invention discloses a PVC film blowing machine, which comprises an extrusion device, a die head, a frame, a first traction device, a water tank, a second traction device and a rolling mechanism, wherein the die head is arranged on the extrusion device; the PVC film blowing device is characterized in that the PVC film blowing device also comprises a rotating mechanism which is arranged above the water tank, and provided with a rotating table; the rotating table is movably arranged on the frame and is connected with a motor in a transmission way; the roiling mechanism and the second traction device are arranged on the rotating table; and the water tank is connected with an up-down lifting device. The PVC film blowing machine adopts the technique that the upper rotation of the rolling mechanism and the automatic lifting of the water tank are combined, thus achieving the purposes that the film blowing machine can continuously work for long time, the service life of the die head is long, the pressure in a film tube can be automatically regulated in the film production process, and film products produced by the film blowing machine have uniform thickness and good quality.