The invention provides an improved PVC membrane blowing machine, belongs to the technical field of membrane blowing machines and aims at solving the problem in the prior art of low membrane blowing efficiency. The improved PVC membrane blowing machine comprises a base, wherein a mounting plate I and a mounting plate II which are arranged in parallel are fixed to the base; the base is provided with a melting mechanism which is capable of melting raw materials; a membrane blowing mechanism capable of blowing out a membrane material is arranged on one side of the melting mechanism; a cooling mechanism capable of cooling the membrane material is arranged below the membrane blowing mechanism and is composed of a water tank, a cooling pipe which is connected with the water tank and a waste water tank which is connected with the cooling pipe; a drawing roller III is arranged above the cooling pipe; a cutting mechanism capable of cutting boundary materials is arranged above the drawing roller III; a recovery mechanism capable of recovering wastes is arranged above the cutting mechanism; a compaction roller I and a compaction roller II are also arranged between the mounting plate I and the mounting plate II; and a material receiving mechanism capable of rolling the membrane material is arranged on one sides of the compaction roller I and the compaction roller II. The improved PVC membrane blowing machine has the advantage of high membrane blowing efficiency.