Abstract: This paper reported a study on the biodegradation of poly (butylene succinate) (PBS) film as degraded substrate, the degradation behavior of PBS film by a Pseudozyma Antarctica Lipase, Lipozyme CALB. The effects of acidity, temperature, enzymatic concentration and degradation time on the degradation of PBS film were investigated, and then the post-degraded films were characterized by scanning electron microscopy, thermogravimetric analysis and differential scanning calorimetry. The degradation products were also analyzed by mass spectrometry. The results indicated that the optimum conditions for the degradation of PBS film by Lipozyme CALB were obtained at an acidity of pH 7, a temperature of 50 ℃ and an enzymatic concentration of 20 U/mL, and a weight loss of 90 wt % was achieved for the PBS film degraded for 24 h at these conditions. The morphologic observation indicated that the surface of PBS film became more and more rough, and some holes appeared with increasing degradation time. The thermal analysis results demonstrated that the crystallinity of the degraded film was found to increase with the increase of degradation time, but their thermal stability trended to increase gradually. The mass spectrometric analysis indicated that the PBS film was degraded into 1,4-succinate and succinate-butanediol, but no 1,4-butanediol was found.