Poly(butylene adipate-co-terephthalate) (PBAT) copolyester, which has good processing properties, is a new biodegradable synthetic polymer material in recent years. However, it is not satisfied with the mulch requirements because of its high cost and low mechanical strength. The mulch films of ternary blends including PBAT, polylactide (PLA), and poly(propylene carbonate) (PPC) are successfully prepared by extrusion blending and film blowing. The effect of different blow-up ratios (BUR) on the mechanical of mulch films was investigated. The 64/20/16 wt% PBAT/PPC/PLA mulch film of 3.1 BUR shows good mechanical properties. The tensile strength is as high as 43.0/37.6 MPa (MD/TD) while the elongation at break reaches 160/450% (MD/TD). The addition of PLA improves the strength of the mulch film, and the addition of PPC improves the barrier performance of the mulch film. It demonstrates that the PBAT, PPC, and PLA have partial compatibility from DMA and DSC analysis. After adding high-efficiency hindered amine light stabilizers, the mulch films have good light stability and their elongation at the break still exceeds 100% after 100 h of UV irradiation. [ABSTRACT FROM AUTHOR]