The invention provides a merging unit quantity measurement simulation system for an intelligent transformer station, and the system is characterized in that the system comprises a host, a communication module, a synchronous clock, and an analog signal output module; the host achieves the time synchronization with the analog signal output module and a merging unit through the synchronous clock; the host achieves the data interaction with the analog signal output module and the merging unit through the communication module. The invention also provides a closed-loop testing method for the merging unit of the intelligent transformer station. The system and method can achieve the remote measurement and closed-loop testing of the analog quantity of the merging unit of the intelligent transformer station, do not need manual operation, and can quickly achieve precision testing with no need of a measurement and control device or a background system.