<p>The characteristics of soil organic carbon (SOC) and soil organic nitrogen (SON) mineralisation and greenhouse gas emission in paddy field under the condition of rice-crayfish co-culture (RC) were studied. We took into account two factors: tillage patterns (rice monoculture (RM), RC8 and RC15, indicating 8 and 15&#xa0;years, respectively) and different water-holding capacity (WHC) levels ( 30%, 60% and 90%). RC (RC8 and RC15) significantly affected total nitrogen (TN), organic carbon, nitrate nitrogen, and ammonium nitrogen contents of the soil as compared to RM. The carbon mineralisation, nitrogen mineralisation and the global warming potential (GWP) of RC8 and RC15 were higher or significantly higher than those of CM. The carbon and nitrogen mineralisation and soil GWP of 60% WHC were significantly or significantly higher than those of 30% WHC and 90% WHC under different water content conditions. At 30%, 60%, and 90% WHC, cumulative N₂O emissions increased by 19%–34%, 12%–33%, and 17%–32% in RC soil than in RM soil, respectively. RC soil showed higher soil mineral N content and 31.6%–60.9% higher GWP compared with those in RM soil, indicating that RC had higher mineral N support, while also having higher carbon emission risk. Long-term rice-crayfish co-culture significantly facilitated soil nutrient, and significantly increasing the global warming potential. The increase in the global warming potential of rice-crayfish co-culture system was determined by soil nutrient factors rather than soil moisture. Therefore, we suggest that N fertilizer could be reduced to a certain extent for long-time rice-crayfish co-culture fields, and other effective low-carbon measures (e.g., Suitable field moisture management) could be adopted to reduce the global warming potential.</p>