Abstract: The "carbon neutrality" and "carbon peaking" objectives are propelling China's urgent energy structure transition toward renewable energy sources. As the dominant primary energy, coal must strike a balance between clean utilization and energy security. Notably, over half of China's medium−deep coal resources are unsuitable for conventional mine mining, making underground coal gasification (UCG) a pivotal technology for their development. This study addressed the critical challenges in UCG industrialization, namely the high storage and transportation costs of H₂ and the unclosed−loop treatment of CO₂ emissions. A novel coupling technical scheme was proposed, integrating three−stage underground coal gasification (UCG−Ⅲ) with near−well CO₂ hydrogenation to produce methanol. UCG−Ⅲ is a new generation of clean coal conversion technology, whose core lies in using CO₂ as both a product and a gasification agent, and achieving efficient utilization of coal and internal circulation of CO₂ through a three−stage process design. The gasification reaction pathway was optimized by this innovative approach to generate hydrogen−rich syngas, which is directly utilized for wellhead CO₂ catalytic conversion. Through this, simultaneous on−site hydrogen energy consumption and high−value utilization of carbon resources were achieved. Experimental and economic analyses demonstrated that storage and transportation costs were significantly reduced by 47% compared to traditional methods, and CO₂ emissions were lowered by up to 80% through underground CO₂ recycling. The dual value of coal as both an "energy service provider" and a "carbon−based material supplier" was validated in this study, paving the way for environmentally friendly and economically feasible clean coal utilization. Current challenges include enhancing the controllability of the three−stage gasification process and developing low−cost skid−mounted methanol conversion equipment. Future research will focus on optimizing process control via multi−physics field model coupling, developing efficient catalysts, and improving system integration to facilitate large−scale industrial application. This work provides a critical technological pathway for China's fossil energy transition toward carbon neutrality.