The invention discloses a protocol adaptation network element and a using method thereof in a communication sub-network. The protocol adaptation network element comprises a communication processor, a communication network management protocol stack, a protocol detection unit, an interface protocol adaptation unit and a network management output unit, wherein the communication network management protocol stack comprises a protocol database with a plurality of communication network management protocols and a network management information model. The using method comprises that: the protocol adaptation network element accesses the communication sub-network, constructs the communication network management protocol stack, receives a network management data packet, identifies the communication network management protocol, realizes network management information model conversion, processes and responds to a network management data message, and performs output port network management communication protocol detection, the communication network management information model conversion and network management data packing and transmission. By the protocol adaptation network element and the using method thereof, the whole communication sub-network can be monitored only by a set of network management system, the compatibility of different types of communication network elements in the communication sub-network is improved, the effective communication of network management information among the different types of communication network elements is ensured, and the problem of network management control over the complex communication sub-network consisting of a plurality of types of network elements is solved.