Abstract: In order to study the effect of straw returning to the field with Organic Matter-decomposing Inoculants (OMIs) on the yield of rice, the decomposition of straw and soil nutrients in paddy field. A field experiment was carried out in the Jianghan Plain. Through it, we wanted to obtain an appropriate indicate to evaluate OMIs and straw direct-incorporation technology for this region. The results showed that, yield increased 5.0%, through straw returning. Straw accompanied with OMI 2 could increase total shoot dry matter and yield, which were 1125 kg/hm2 and 435 kg/hm2, and increment rates were 6.9% and 7.6%, respectively. The characteristics of decomposing results showed OMI 2 was the best product and the cumulative decomposition rate of straw was 30.3% on 15 days, but OMI 3 had not work compared with CK. Then, the rate of decomposition was slowed down, and the differences among treatments reduced. The characteristics of nutrients release indicated that the C, N and P released quickly on 30 days. The effect of OMI 1 and OMI 2 were better than OMI 3 in the end (100 days). The release of potassium was more than 95% in 5 days, which indicated OMIs had no effect on K. The correlation analysis of these indicates showed the method of mesh bag to detect the cumulative decomposition rate of straw was the most simple and effective tool. Short-term straw returning had no significant effect on soil organic matter and total nitrogen content. In actual production, the straw should be incorporated 5 days before rice transplanting to reduce the toxic action of straw decomposing on roots and strengthen early nitrogen supply to ensure the crop nutrient demand.