The work aims to research the effect of the content of ATBC on the performance of PLA/PCL composite packaging film. Different contents of ATBC were mixed with PLA and PCL resin evenly, and then the mixture was melt extruded to prepare ATBC/PLA/PCL blend film first by pelleting and then film blowing. Scanning electron microscope analysis on the prepared packaging film was conducted to observe the microscopic profile. Mechanical property texts were done to obtain the elongation at break and tensile strength. DSC test was conducted to analyze the melting crystallization behavior. Oxygen permeability test was employed to get the barrier property. ATBC had an effective influence on improving the compatibility of PLA and PCL and significantly enhanced the elongation at break of the composite film, from 6% to 250%. As the content of ATBC increased, the oxygen permeability of composite films increased first and then decreased, and it influenced the glass transition temperature and melt temperature of composite films. When the mass of ATBC accounts for 8% of the total mass of resin, the blend film has the optimal performance.