Abstract: Food security is a crucial pillar for maintaining national stability and long-term peace, and increasing the multiple cropping index is an effective approach to tapping the potential of arable land and enhancing food production capacity. This study optimized the suitability evaluation factor system for double-cropping rice in paddy fields. The methods of the evaluation and constraint factor analysis, multi-factor weighted evaluation model, and a four-quadrant approach were employed to conduct a comprehensive suitability evaluation and spatial optimization for double-cropping rice cultivation in Hunan Province. The results indicated that: (1) The overall suitability for double-cropping rice cultivation was relatively high, with the majority of suitable areas classified as moderate to high suitability zones. Specifically, the proportions of high, moderate, low, and unsuitable suitability areas were calculated as 31.05%, 35.83%, 20.00%, and 13.12%, respectively. This implied that most regions had favorable conditions for double-cropping rice cultivation. (2) In 2020, there was an additional potential area of 2540.07 thousand hectares for double-cropping rice cultivation in Hunan Province, which accounted for 51.68% of the total suitable paddy field area. Among these, the potential increase in rice yield was 5.31 million tons, representing 20.13% of the total rice production in Hunan Province in 2020, which indicated the substantial potential for yield enhancement. (3) Based on a comprehensive analysis of current farming conditions and suitability evaluation results, Hunan Province is divided into four optimization zones for double-cropping rice cultivation structure, i.e. the key protection areas, the priority remediation areas, the status quo protection areas, and the structural adjustment areas. The number of counties corresponding to each optimization zone was 32, 42, 21 and 27, respectively. It was recommended to implement differentiated governance and management measures for each zone to maximize the utilization of regional resources and potential, to ensure sustainable agricultural development. The findings of this study provided scientific support for the formulation and implementation of differentiated rice planting subsidy policies in Hunan Province. Additionally, they offered strategic guidance for optimizing the double-cropping rice cultivation structure, to enhance the multiple cropping index, and to ensure regional food security. Implementing these measures would enhance the utilization of valuable arable resources, boost food production capacity, and contribute to both national food security and high-quality agricultural development.