The work aims to discuss the preservation influence of chitosan-based antibacterial preservative film (CAPF) on the storage of postharvest snap bean. Weight loss rate, decay rate, color difference, respiration intensity, Vc content, reducing sugar content, superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were used as indexes to study CAPF on snap bean preservation. It turned out that CAPF had a good preservation effect. When stored for 18 days, the weight loss rate of CAPF treatment group was 15.27%, which was 62.71% of the control group; the decay rate of CAPF treatment group was 6.3%, which was only 31.3% of the control group. Compared with other treatment groups, CAPF treatment group can effectively reduce the etiolation rate, inhibit the rise of respiratory intensity, delay the decline of Vc and reducing sugar content, maintain SOD activity, and effectively inhibit the accumulation of MDA. CAPF can effectively improve the storage quality and can be used for snap bean preservation.