Abstract: According to the fact that corn straws remain or burned in the field in hilly and mountainous areas of Southwest China, which causes organic matter waste and serious atmospheric pollution, it is necessary to develop an efficient method to compost the corn straws. In the present experiment, corn straws were placed on the landside and land corner for composting with thermophilic cellulous bacteria inoculated, chemical nitrogen and nitrogen absorption agent added, and then covered with polyethylene film (biocomposting). Thereafter, fluecured tobacco grown in the same land was fertilized with the compost to study the fertilizer effect. The results showed that the temperature in biocompost increased quickly (over than 35 ℃ within 2 to 3 days) but decreased slowly compared to natural composting (control). In the biocompost, temperature over than 50 ℃ lasted for about 15 days and the number of bacteria was 100 to 1000 times higher than in the control despite that microbial groups decreased in the high temperature period. After 90 days of biocomposting, corn straws contained water less than 25% with pH 6.14 and showed brown or black color and fragmental or farinose physical state, indicating good decomposition and humification. Meanwhile, the active organic matter and nutrients, including N, P and K, were significantly increased. The yield, mean price, economical output of fluecured tobacco leaves were increased and the leaf quality was improved by application of chemical fertilizers plus the compost at the ratio of 1:1. Therefore, biocomposting could utilize efficiently corn straws and eliminate air pollution, which is worth popularization in hilly and mountain areas.