The work aims to compare the plasticizing effect of different mass fractions of alcohol ether carboxylate (PPEC), a novel green plasticizer, on PPCP/PBAT composite films. The PPEC was made in the laboratory. The PPCP/PBAT/PPEC composite film was prepared by blowing the film after twin screw with PPCP and PBAT as the base materials. The composite film was characterized from various aspects such as microscopic morphology, thermal properties, optical performance and mechanical properties. The cross section of the composite film gradually became smooth and flat from the obvious island morphology and phase separation interface. The FTIR spectra of the composite film demonstrated the presence of PPCP and PBAT, which was accompanied with the transition from the free state hydroxyl group to the conjugated hydrogen bond. The glass-transition temperature of the composite film decreased gradually. The light transmittance tended to increase and haze tended to decrease, but the changes were not significant. PPEC effectively improved the interfacial compatibility between PPCP and PBAT. The elongation at break of the composite film reached 520%, and the elasticity modulus and yield strength of the composite film were reduced to 618 MPa and 4.83 MPa, respectively. Therefore, PPCP/PBAT/PPEC composite film has good plasticizing effect, and the optimal dosing of PPEC is 2.0%.