Abstract: To study the effects of straw returning on the contents of soil organic matter and nutrients, microbial biomass-C, N, soil enzyme activities and rice yield, a long-term experiment was conducted in an acid paddy field of Hezhou, Guangxi, China. The results showed that compared with the control, the contents of soil organic matter and nutrients were significantly higher with straw returning treatment. The contents of soil organic matter, total nitrogen, available phosphorus, available potassium and slow-available potassium were increased by 7.00%, 3.57%, 3.49%, 4.11% and 3.39%, respectively; Soil microbial biomass-C, N was also significantly higher with straw returning treatment, increased by 37.4% and 21.8%, respectively; The straw returning treatment increased urease activity, catalase activity, and sucrase activity by 67.4%, 12.4%, and 7.43%, respectively. Rice yields with straw returning treatment, straw returning combined with decomposition agent treatment, increased the actual rice yields by 4.85% and 5.96%, respectively.