Abstract: Water scarcity and rising greenhouse gas emissions had been the problems facing the sustainable development of agriculture. Rice planting was a major contributor to water consumption and methane (CH4) emissions in agriculture. Water management was an effective measure for water saving and CH4 mitigation. However, the deletion of the applicability assessment of methane mitigation technology limited the formulation of an accurate carbon reduction policy for regional rice production and the improvement of China’s carbon peaking and carbon neutrality strategy. Based on the analysis of rice production status in Hunan Province, China and the regional applicability evaluation of Alternate Wetting and Drying (AWD) CH4 mitigation technology, this study aimed to provide precise cooperative measures for high yield and emission reduction in major rice-producing areas in Hunan. This assessment method was developed by the International Rice Research Institute (IRRI) and had been well-evaluated in many Southeast Asian counties. The rice production data (2016-2019) and meteorological data of various cities (1960-2017) were collected in Hunan. The AWD technique was based on the rice field water balance model and combined with Geographic Information System (GIS) to evaluate the applicability and weighted CH4 mitigation potential of this technique in Hunan Province. The method assumed that rainfall was the only input water source. Meanwhile, input data needed to be highly accessible. Soil and climate data were limited factors to improve this model. Therefore, more normalized and scientific management was required for data collection. The method to assess CH4 emission in rice field was adopted by Guidelines for the provincial greenhouse gas inventories (for trial implementation) which were considered by Intergovernmental Panel on Climate Change (IPCC) tier 2 method. The emission factor method would be used as the main method for accounting CH4 emission in rice fields. The advantage of the emission factor method was that it was simpler, and saved more resources and manpower. However, the emission factor affected the accuracy of CH4 emission accounting. It needed to evaluate CH4 emission with local emission factors. In this study, the methane emission factor of continuous flooding and AWD technique was elected by our group’s long-term field research as well as the literature review. The result indicated that, from 2016 to 2019, the sown area of rice in Hunan showed a downward trend and double-season planting was gradually changed to, partly at least, single-season planting. The yield of rice increased steadily, and the annual yield of single-cropping rice was 7 259 kg/hm2 in four years, which was 21.68% and 13.19% higher than that of early and late rice, respectively. At the city and county levels, there was a significant spatial-temporal difference in the applicability of AWD. Compared with early and single-cropping rice, late rice was more suitable for the AWD technique. Precipitation was the key to the effect of AWD suitability assessment. Hunan’s low precipitation and higher temperature during late rice growing season provided implementation conditions for AWD. For the growth duration of rice, it showed that the AWD suitability of early and single-cropping rice was better in the later period of rice growth duration. However, the AWD technique was suitable for late rice except for tillering stage. AWD had great CH4 mitigation potential (51.16%) in Hunan province. Considering the applicability scenario, AWD could reduce 493 600 t of CH4 emission, accounting for 5.54% of CH4 emission from nationwide paddy fields. There had many limitations to the adoption of AWD. It needed complete infrastructure, stable irrigation water, technical guidance and necessity to consider the economic benefits of implementing units. To ensure the rice supply for food security, implementing dynamic AWD precise control technology according to local conditions was the key measure for low-carbon transformation and high-quality development of rice production in major rice cropping regions in Hunan.