The utility model relates to an intelligent management case for the online monitoring system of a distributed substation, which comprises a power supply distribution module. The power supply distribution module is connected with a power supply module. The power supply module is connected with a communication distribution module. The power supply module is connected with a bus bar pt voltage signal processing module. After voltage and current conversion is conducted, bus bar pt voltage signals in a main control building are supplied as bus bar pt voltage signals for dielectric loss monitoring and lightning arrester resistive current monitoring. An Ethernet switch in a case conducts uniform management to communication signals to establish a local area network. The Ethernet switch in the case accesses the communication signals to the communication room of the main control building through an optical cable, and therefore the main control building can access to each online monitoring case through one optical cable only. One loop of power supply is only required to be led out for the power supply distribution management in the case and the power supply to the online monitoring case can be realized. The intelligent management case for the online monitoring system of the distributed substation has the advantages that the number of buried cables for the distributed online monitoring system is decreased and the material cost and the construction cost are reduced.