Abstract: To address the requirements of multi-payload large field of view, large mass, high load-bearing capacity, large size, and high stiffness for the HY-3A Satellite, a triangular arrangement payload configuration layout scheme based on the payload expansion cabin was proposed, and the load-bearing path of the satellite was optimized. By adding two short partitions to the main load-bearing path, the load capacity of the satellite was increased from 1 200 kg to 1 500 kg, and the overall stiffness of the satellite was improved effectively. The verification results demonstrate that the proposed triangular arrangement payload configuration layout satisfies the large field of view observation demands for three optical payloads, each exceeding 200 kg in mass, providing a reference for the configuration layout design of similar satellites in the future.