Abstract: Promoting the green and low-carbon development of the grain industry is essential for ensuring national food security and achieving China’s “Dual Carbon” goals. Jiangxi Province, a major grain-producing region known as the “Granary of South China”, has distinct ecological and industrial advantages, making it a representative case for such transformation. This paper provides a comprehensive analysis of the current state of the grain industry in Jiangxi, focusing on its stable planting scale with rice as the dominant crop, optimized regional layout forming core production zones, enhanced seed industry innovation capabilities, and continuously improved agricultural infrastructure. The study elucidates the intrinsic logic of green and low-carbon development in the grain industry, which centers on the core principles of “reduce, recycle, improve, and extend”. It further summarizes the practical outcomes and environmental benefits of several typical models implemented in Jiangxi, including the “winter crop + double cropping rice” system that enhances annual light utilization and carbon sink capacity, the ratoon rice model that achieves “one planting with two harvests” and resource conservation, the green planting-breeding recycling model that facilitates the resource utilization of agricultural waste, and the integrated rice-aquaculture system that constructs a mutually beneficial paddy ecosystem. Despite these achievements, the green transition of Jiangxi’s grain industry faces multiple challenges. These include tightening resource and environmental constraints, such as limited arable land per capita, soil acidification, and water resource pressures; insufficient scientific and technological support, as evidenced by weak innovation in the seed industry innovation and lagging green technology R&D; low comparative benefits for grain farming, which dampens endogenous motivation for green practices; short and weak industrial chains coupled with limited brand market competitiveness; and inadequate policy coordination and insufficient driving force among stakeholders, hindering the formation of a long-term mechanism. In response, this paper proposes a systematic practical pathway comprising several key aspects: strengthening technological empowerment and talent cultivation to build a green innovation highland; improving agricultural infrastructure conditions, including high-standard farmland and water resource management, to solidify the production foundation; implementing a dual-drive strategy focusing on both variety improvement and brand building to enhance the market value of green products; promoting the optimization and upgrading of the entire industry chain to improve industrialized operation levels; and perfecting the green policy support system to reinforce factor guarantees; and explore the construction of green low-carbon development evaluation system, leading the transformation of industrial science. These recommendations aim to provide valuable references for fostering green, low-carbon, and high-quality development in the grain industry of Jiangxi and similar regions within the middle and lower reaches of the Yangtze River.