Abstract: Effect of different straw-decomposing inoculants on decomposing efficiency of the straw returned to paddy field was studied. The results showed that applying straw-decomposing inoculants could move up decomposition of treated straw by 4-6 d earlier; the rice plants grow strongly with good coloring at later stages, effectively promote tillering ability in the low-node position of rice, increase effective panicles, 1000-grain weight, seed setting rate, rice yield and economic benefit, also increase the contents of organic matter, total nitrogen, available phosphorus, available potassium and other nutrients in soil, especially the content of available potassium was increased significantly. Among four kinds of straw-decomposing inoculants, ‘Jinkuizi’ has a better straw-decomposing efficiency.