Abstract: This study focuses on the capacity optimization problem of a distributed gas triple supply system in a regional energy station in Hunan Province, aiming to propose a demand based capacity allocation method. In the context of achieving China's "dual carbon" goals, this article explores the key role of distributed gas triple supply systems in improving comprehensive energy utilization efficiency and achieving energy cascade utilization. At the same time, compared with traditional energy systems, it has multiple advantages in terms of economy and technology. By predicting the building formats and building areas within the region, energy consumption simulation software is used to estimate the heating and cooling loads of energy stations in the area. On this basis, from an economic perspective, a comparative analysis was conducted on the capacity allocation schemes of 6 MW and 8 MW power generation, and the conclusion was drawn that the 8 MW scheme has significant advantages in both economy and operational efficiency. In addition, this article also reviewed the capacity of the generator set to ensure that it meets both technical requirements and economic efficiency standards. The research results provide certain reference value for promoting the construction of regional energy structure.