Abstract: With the rapid depletion of shallow mineral resources, an increasing number of mines are stepping into deep mining to ensure resource continuity, which generally forms a coordinated production model that includes both existing shallow production systems and new deep projects. Given the complex production patterns of both multi-mining areas and multi-sections formed during the process of deep mining, how to achieve geological resource continuity, stable production capacity, balanced supply grade, and sustainable economic benefits are the key issue to be addressed in the mining scheme during the transition to deep-area. When an underground mine transitions to deep mining, it is necessary to steadily advance the production task and maintain the steady growth of metal quantity and economic benefit. Therefore, to maintain production continuity and stability, it is necessary to optimize the production plan for underground metal mines. Considering the situation of multi-section mining submontanely, the Sanshandao gold mine is used as a case study to investigate the complex production layout of multi-section mining simultaneously subjected to constraints of production capacity balance, grade requirements, and other production system capacities through in-depth analysis of the production capacity continuity in the process of mining transition to deep mineral resources. An optimization model is constructed aiming at maximizing the comprehensive resource exploitation value of multi-section mining. A mathematical planning model for the continuation and optimal allocation of production capacity during the transition period of deep mining is constructed with the optimization goal of maximizing the comprehensive exploitation return of resources from multiple mining areas, taking the constraints of overall capacity succession, balanced output grade, and capacity limits of each mining area into account. Following the solution of the Sanshandao gold mine’s production capacity, succession during the transition to deep-area is obtained. The model considers the coordination and succession of multiple mining areas and sections in terms of time and space, and it achieves a smooth production system transition from shallow to deep areas through accurate evaluation of existing operation conditions and optimal allocation of production factors, all while ensuring the production tasks and economic efficiency targets are met. The optimization model is programmed in Python, and it is solved using the Gurobi software. The results show that the best capacity continuation and production task allocation schemes are obtained to effectively ensure benefit improvement as well as production capacity balance and stability. The example application validates the scientific and efficacy of the optimization model, which can be used by other mines to optimize production plans when switching to deep mining.