An on-line verification of relay settings and early warning system of protective relaying is researched and designed based on MAS（multi-agent system）. The system makes use of the intelligent character of agent to analyze the real time parameters of the networks and to accurately form the real-time operation situation. The parallel calculation technology is adopted in the system to enhance the calculation speed based on the support of MAS. CORBA（common object request broker architecture） software bus， CIM（common information model） of IEC 61970 and protection function logical node of IEC 61850 are connected together to develop an information model of electric power equipments involved in the system， so the extensible and opening ability of the system can be improved.