The work aims to research the effect of PCL content on the performances of PLA/PCL blending packaging film, so as to improve the toughness of PLA. PCL and PLA resins with various mass ratios were mixed evenly, and then PLA/PCL blending films were produced by melt extrusion method. Mechanical properties of the prepared blending films were tested to obtain tensile strength and elongation at break. Scanning electron microscope was used to analyze the fracture profile. DSC was used to test and analyze the crystallization behavior. Oxygen permeability test and water vapor transmission test were used to get the barrier property. Based on the findings of scanning electron microscope and infrared spectroscopic analysis, PLA and PCL were two-phase structures and the interface was incompatible. The mechanical properties found that, the elongation at break of PLA would not be improved dramatically when the mass of PCL was under 20%. The elongation at break of PLA was increased from 2.9% to 290% when the mass of PCL was 50%. Moreover, DSC showed that the added PCL contributed to decreasing the glass transmission temperature and increasing the degree of crystallinity. The results of barrier properties proved that, with the increase of PCL mass ratio, the oxygen permeability and water vapor transmission of the blending films were reduced and the barrier properties were improved. The added PCL is likely to improve the elongation at break of PLA. When the mass ratio of PCL to PLA is 3:7, the blending film has the optimum performance.