Abstract: Field experiments were carried out in cotton field-seeded after barley (rape) to explore the effects of film mulching on biomass accumulation and yield in 2016 and the effects of film mulching on soil physical and chemical properties, biomass accumulation and yield in 2017. Four treatments, including planting without mulching (CK), planting with polyethylene film mulching(PM) and two kinds of biodegradable film mulching(AM and BM), with three replicates were conducted. The results showed that the mean soil water content and soil temperature in 0~20 cm soil layer increased in all mulching treatments compared with that in CK. The soil available N, P and K increased with highest value in the treatment of PM and BM at cotton seedling and budding stage respectively. The soil organic content increased in the treatment of BM and decreased in PM and AM compared with that in CK. The soil enzyme activities of urease, invertase, catalase, and neutral phosphatase decreased at seedling stage but increased at budding stage with higher value in the treatment of PM and BM respectively. The biomass accumulation initiated and terminated earlier in all film mulching treatments than that in CK. The maximum biomass and its maximum speed increased with optimized characteristics in the treatment of BM. Yield and yield ratio before frost was higher in film mulching treatments, especially in BM, than that in CK. In sum, biodegradable film mulching can promote seedling growth due to the improvement of soil physical and chemical properties, which may contribute to improving yield and the yield ratio before frost.