Abstract: In order to solve the paradox between similarity and diversity of network protocols, the cost of system resources for different protocols and different implementation methods, and the complexity of management and maintenance of protocols, realization of the generality by using object oriented methods and concept of virtual machine is proposed,a protocol implementation method based on protocol engine is given, and its structural character and some considerations in application are analysed,based on the analysis of basic subjects in OSI protocol implementation. Efficiency is regarded as the main evaluation factor. Also given are implementation schemes of the network management module and gateway router while applying protocol engine in the Java environment.