The invention provides an SNMP-based transmission network unified network management system, belongs to the technical field of power communication network management, and specifically relates to an SNMP-based transmission network unified network management system. The invention provides an SNMP-based transmission network unified network management method to well shield underlying transmission protocol differences. The method includes following steps: step 1, a management station sends a control data packet, employing an SNMP management protocol, and performs transmission through a non-connection-oriented UDP; step 2, a request queue receives the control data packet from the management station; step 3, protocol analysis is conducted on the received data packet, and a communication protocol stack, a management information model and a network management protocol type are obtained and stored in an information base; and step 4, a sub-agent module is delegated to collect and analyze information of managed equipment, the information is stored in a data processing module, and the protocol type of the managed equipment is recorded in the processing module of the management information model.