Abstract Syntax Notation One (ASN.1) plays an important role in many network protocol stacks. Some institutes use compiler-based approach to develop their ASN.1 module. However, this approach has some disadvantages, such as low efficiency, redundant codes, etc, and the module may become one of the performance bottlenecks in high-speed network communication. This paper discusses the requirements of ASN.1 module in network protocols, and analysis the compiler-based approach. Later a novel approach is proposed. It does not contain numerous encoding & decoding routines, but use a tree-like structure called "database definition" to store the necessary ASN.1 syntax information, and uniform functions to perform the encoding & decoding procedure.Using this method, a substantial reduction in code size was demonstrated (up to 90% reduction in the code size taken up by marshalling routines), and the improved efficiency also tested its superiority.