Abstract: In the development and testing of substation monitoring systems, thorough validation of IEC 104 protocol functionality is critically important. However, in actual testing, the lack of dedicated server-side simulation tools often leads to incomplete verification. To address this issue, this paper investigates and implements a server-side simulation tool for the IEC 104 protocol tailored to substation communication. The tool employs a multi-threaded architecture to efficiently simulate multiple independent slave station channels, supporting concurrent communication with the monitoring systems. It not only satisfies single-point functional testing but also flexibly constructs complex multi-channel scenarios, thereby effectively improving test coverage and validation depth.