Abstract: The integrated rice-crayfish system is an emerging complex ecological system of planting and breeding in the middle and lower reaches of the Yangtze River in China. Based on the field experiment, the aeration methods were used to study the effects of winter flooded fallow + no straw returning (W), winter flooded fallow + straw returning (WS) and winter flooded fallow + straw returning +crayfish farming (WSC) on ammonia volatilization loss in paddy fields. The aim of this study is to provide data support for the evaluation of nitrogen loss in the integrated rice-crayfish system. The results show that the ammonia volatilization in the rice growth stage accounted for 5.84%-6.49% of the nitrogen application rate in the current season, which mainly occurred during the rice base fertilizer stage and tillering fertilizer stage, and the ammonia volatilization loss in tillering fertilizer stage accounted for the highest proportion of tillering fertilizer. Compared with the W treatment, the WS treatment increased the ammonia volatilization flux and ammonia volatilization loss during the base fertilizer stage, but the ammonia volatilization loss during the tillering and earing stages had a decreasing trend. In the case of breeding Procambarus clarkii on the basis of the WS treatment, the ammonia volatilization loss in the base fertilizer stage decreased by 15.01%, but the ammonia volatilization loss in the earing stage increased by 29.09%, and the differences reached to significant levels (P < 0.05), but the total ammonia volatilization loss was not much significant different between the W and WS treatments. Ammonia volatilization flux had a very significant positive correlation with NH₄⁺-N concentration and pH of the field surface water (P < 0.01). In conclusion, although straw return to the field under the integrated rice-crayfish system did not reduce the total ammonia volatilization, the characteristics of ammonia volatilization in different fertilization stages were changed, which provided data support for optimizing fertilization mode under the integrated rice-crayfish system and reducing ammonia volatilization in the paddy fields.