The invention discloses a plastic film blanking device. The plastic film blanking device comprises a centralized electric control box, a blanking cutter frame block, an air-liquid pressure cylinder, asupport column pipe, a film machining table, a slide rail transmission groove, a sudden stop button base, an anti-collision shell cover, a trapezoidal blade and a motor box base; the air-liquid pressure cylinder and a guide pipe of the slide rail transmission groove are engaged as a whole; the air-liquid pressure cylinder is provided with a gear transmission mechanism, a gas transmission device,a tooth block switching device, a ratchet rotating mechanism, a shaft rod ejecting device, a hydraulic cylinder compression mechanism, a pneumatic cylinder pushing mechanism and a double-outlet-rod pressure device; the hydraulic and pneumatic cooperation effect of the plastic film blanking device is high; hydraulic outlet water scours and blanks residues, so that the next material blanking qualityis not influenced; and burrs are flatly blown by applying the air pressure to finish the flatness of film surfaces beforehand, so that the quick implementation of later production line is accelerated, the overall working efficiency is improved, and the short-time high-quality operation is achieved.