【Objective】Soil erosion and declining of soil fertility is becoming a severe problem in vegetable fields in South China. In practice, mulching system has become one of the effective measures for solving this problem. However, the study of the different mulching on soil biological properties and bacterial diversity in vegetable fields were rarely investigated.【Method】Soil samples were collected from pepper fields with different mulching treatments in South China. Soil temperature, water contents, soil microbial biomass, enzyme activity were analyzed by traditional ways and bacterial diversity was studied by using high-throughput sequencing techniques. 【Result】The soil temperatures in different layers from the depths of 5 cm, 10 cm, 15 cm and 20 cm were increased 0.05～2.93 ℃, 0.06～1.88 ℃, 0.45～2.16 ℃ and 0.23～2.46 ℃, respectively. Meanwhile, soil water content was increased 13.3%～19.4% under different mulching conditions which compared to control. By contrast, soil pH was also raised from 0.01 to 0.19 under different mulching conditions which compared to CK. In addition, the enzyme activity and microbial biomass were also significantly increased which relative to type of the mulch, i.e. in turn, colorless transparent film, black film and silver film which are all made of polyethylene. Soil bacterial diversity, Flavobacterium, Lysobacter, Alcaligenes Sphingomonas and Bacillus turned out to be the dominant groups and the soil bacteria therein were higher in richness, diversity and evenness in soils under different mulching conditions which compared to CK. In particularly, soil bacteria, such as Lysobacter and Bacillus, that are capable of protecting the ecology and promoting plant growth, were found accumulating in the soils of mulching conditions. 【Conclusion】 The colorless transparent plastic film mulching is the best for increasing soil temperature, water content and enzyme activity. And all the mulching treatments not only can improve the soil physical and chemical characteristic, increase the soil microbial biomass and enzyme activities, but also can accumulate some of the plant growth promoting bacteria (PGPB) in pepper fields. All the findings indicate that instead of degrading soil quality of the pepper fields, the current practice of film mulching will help build up soil fertility and improve soil health