Abstract: Effects of straw returning and applying decomposition agent on the yield of late rice and soil fertility were studied. The results showed that the decomposition agent could obviously accelerate the decomposing speed of rice straw, and straw returning into paddy field could improve the soil physical and chemical properties and enhance soil fertility. In addition, the rice yields in the treatments that applying decomposition agent “Feilaoban” and “Ningliang” were increased at very significant level.