The utility model provides a communication object server based on the IEC61850 standard in an on-line monitoring system. The communication object server is composed of a CPU unit, a power supply unit, four asynchronous serial port units, four Ethernet port units, a hardware watchdog unit, and a GPS module unit. The power supply unit is connected with the CPU unit and the GPS module unit to give working power. The CPU unit is connected with the four Ethernet port units and the four asynchronous serial port units. The CPU unit is connected with the GPS module unit via a bus. The CPU unit is connected with the hardware watchdog unit via the bus. The communication object server can realize the organic unification of standardization and safety, the comprehensive coordination, and the reasonable and scientific utilization, so heterogeneous and isolating subsystems in a transformer station can be utilized coordinately, reasonably, and scientifically, and the function standards and technical requirements of each subsystem can be made uniformly. Besides, external communication hardware interfaces can be unified, and production and management information can also be published uniformly.