The invention discloses a high-strength environment-friendly PVC shrink film and a preparation process thereof. The PVC shrink film is prepared from the following raw materials in parts by weight: 88-100 parts of polyvinyl chloride, 6-10 parts of ethylaniline, 10-15 parts of dioctyl phthalate, 5-10 parts of MBS resin, 1-3 parts of a plasticizer, 2-4 parts of a heat stabilizer, 1-3 parts of an internal lubricant, 1-2 parts of an external lubricant and 3-5 parts of a processing aid. The PVC raw material is modified by virtue of an anti-impact enhancer, the plasticizer, the heat stabilizer, the internal lubricant, the external lubricant and the like through a polymer blending modification technique, and after being mechanically mixed with PVC, a modifier is well dispersed in a PVC matrix, sothat the heat stability of PVC is improved, the processing performance is improved, and meanwhile, the tenacity and impact resistance of PVC can be substantially improved.