The work aims to improve the packaging properties of PLLA-based films and to investigate the effect of PLLA-based films on grape preservation during storage. Poly (L-Lactic Acid Itaconic Acid Butanediol) (PLBI) was prepared by introducing Poly (Itaconic Acid Butanediol) (PBI) on the main chain of Poly(L-Lactic Acid) (PLLA) by melt polycondensation. Poly (lactic acid) copolymer with -OH as a side group were prepared by grafting 3-amino-1-propanol (3AP) onto the side group of PLLA via Michael addition reaction to investigate the thermal, mechanical and gas permeability properties of PLLA/PLBI-3AP film. The grapes were stored after packaging. Through the determination of the composition of the atmosphere, sensory quality and quality loss rate of the grapes in the storage process, the effect of different packaging films on the preservation quality of grapes were explored. Compared with PLLA films, the Tg of PLLA/PLBI-3AP films decreased by 19.9 ℃, the elongation at break increased by 31 times, the CO2/O2 selective permeability ratio increased to 3.0, and the water vapour permeability increased by 44%. The results showed that PLLA/PLBI-3AP films inhibited spoilage and improved sensory quality of grapes. The use of PLLA-based films can extend the shelf life of grapes to 21 days.