Abstract: The new quality productive forces in paddy fields represent an endogenous driving force that enhances rice production efficiency within the broader framework of new quality productive forces. The force takes the paddy field ecosystem as the target, scientific and technological innovation as the engine, and the integration of new factors of production into the rice industry chain as the principle, achieving driving effects through the recombination of these factors. The development of new quality productive forces in paddy fields is a critical proposition in the new era for ensuring national food security and advancing high-quality agricultural development. Facing multiple challenges such as technological bottlenecks, economic costs, ecological risks, and farmers’ acceptance, it is worth studying how government subsidy policies can serve as a tool to promote the growth of new quality productive forces in paddy fields. This paper focuses on farming households (the micro-management entities) in paddy fields. With the survey data from 559 farming households in 10 counties of Jiangxi Province, this study constructs benchmark regression, mediating effect, and moderating effect models, and employs methods such as data envelopment analysis (DEA) and Tobit regression to delve into the impacts and mechanisms of government subsidies on the new quality productive forces in paddy fields. The results are summarized as follows. First, government subsidies promote the development of new quality productive forces in paddy fields, which remain consistent following the robustness test and endogeneity treatment. Second, government subsidies demonstrate heterogeneous effects on the development of new quality productive forces in paddy fields, contingent upon risk attitudes of farming households and the land contiguousness, and there is an interactive inhibitory effect between the impacts of risk attitude and land contiguousness on the new quality productive forces in paddy fields. Third, social learning is identified as a significant mediating mechanism through which government subsidies facilitate the development of new quality productive forces in paddy fields. Government subsidies promote the development of new quality productive forces in paddy fields by improving the level of social learning of farming households; Fourth, rice policy-based insurance serves as a moderating factor in the process of government subsidies affecting new quality productive forces in paddy fields, attenuating the positive effect of government subsidies on new quality productive forces in paddy fields. Rice policy-based insurance and government subsidies exhibit a substitution effect. According to the results, it is essential to optimize government subsidy policies, enhance the differentiation of subsidy policies, establish a social learning support system, and improve the coordination mechanism between rice policy-based insurance and subsidy policies.