Abstract: Understanding the effect of nitrogen (N) fertilizer and diatomite application on methane (CH₄) emissions and the temperature sensitivity (Q₁₀) of CH₄ emissions under the ratoon rice system is crucial for optimizing greenhouse gas emissions from paddy ecosystems. A two-year field experiment was conducted from 2022 to 2023 in Jingzhou city, Hubei Provice. Three treatments were set up on this study site: N fertilizer application (N), N fertilizer combined with diatomite application (N+Si), and no N fertilizer application (CK). The CH₄ fluxes were measured by using a closed-chamber method. The rice yield and soil properties were observed. Results showed that compare to CK treatment, both N and N+Si treatment could significantly increase the rice yield of main season and ratoon season(P<0.05). And N+Si treatment significantly increased the rice yield of main season by 3.75%−3.85%(P<0.05), compare with N treatment. The cumulative CH₄ emissions of the entire growth period (main season and ratoon season) in both N and N+Si treatments were significantly higher than CK treatment(P<0.05). But, N+Si treatment significantly reduced the cumulative CH₄ emissions by 23.73%−41.36% in the main season, 17.13%−37.49% in the ratoon season, and 25.99%−36.66% in the entire growth season, respectively (P<0.05) compare with N treatment. Consequently, N+Si treatment significantly reduced CH₄ emissions of per unit yield in both the main season and ratoon season by 26.52%−43.51%, and 18.65%−41.14% (P <0.05), respectively, compare with N treatment. Correlation analysis revealed that the influences of soil properties on CH₄ fluxes were quite differences among treatments and period of rice growing season. The CH₄ fluxes was significantly decreased with the soil Eh (P<0.05) in the main season (P <0.05). But in the ratoon season, the CH₄ fluxes were significantly increased with soil temperature and soil NH₄⁺-N (P<0.05). The CH₄ emission was also significantly positively influenced by the soil temperature during the period of conventional irrigation in the main season. The N+Si treatment had the highest Q₁₀ of CH₄ fluxes with the value of 8.8640, indicating that the addition of diatomite made CH₄ fluxes more sensitive to temperature changes. In conclusion, as a sustainable fertilizer management, combined application of nitrogen fertilizer and diatomite not only increase the yield of ratoon rice but also effectively reduces the CH₄ emissions from ratoon rice system.