The nylon net cages self-made were used to study the characteristics of straw decomposition， nutrient release characteristics， and surface microstructure changes of rice under the disturbance from crayfish simulated in a trenche for aquaculture with rice-crayfish model and with no crayfish as a control in order to investigate the process and characteristics of straw decomposition of rice participated by crayfish under continuous soaking conditions， improve the technology for returning rice straw to the field in the rice-crayfish model， and realize the efficient utilization of straw resources and sustainable development of farmland. The results showed that the average decomposition rate of rice straw in each stage showed a characteristic of fast-slow-fast-slow-fast regardless of whether crayfish participated or not. There was no significant difference in the amount of decomposition， cumulative decomposition rate， and average decomposition rate between the treatment with crayfish and the treatment without crayfish before 150 days. All indexes of the treatment with crayfish were significantly higher than those of the treatment without crayfish after 180 days. The cumulative decomposition rate of rice straw in the treatment with crayfish reached 85.67%， which was 12.35 percentage points higher than that in the treatment without crayfish at 210 days. The cumulative release rate of straw nutrients was in the decreasing order of K>P>N. The cumulative release rate of N in the treatment with crayfish was higher than that in the treatment without crayfish after 150 days. The cumulative release rate of P and the cumulative release rate of total nutrient in the treatment with crayfish were higher trend than those in the treatment without crayfish after 180 days. The cumulative release rate of K in the treatment with crayfish was higher than that in the treatment without crayfish at 210 days. The surface structure of straw treated with crayfish was significantly more damaged than that treated without crayfish after 120 days. It is indicated that the disturbance from crayfish can increase the degree of damage to the surface microstructure of rice straw at the middle and late stages， promote the decomposition and nutrient release of rice straw at the late stage in a trenche for aquaculture with rice-crayfish model.