The authors propose the Protocol Design Production System (PDPS) for a protocol design system using the production systems approach based on OPS5. Using the production systems approach, communication protocols are specified as triples of object-attribute-value, and the occurences of send and receive transitions in the communication protocols can be specified by production rules. The inference of reachable global states and all logical errors are formally defined in terms of production rules. An incremental verification algorithm based on the production systems approach is also presented. From this approach, one can obtain the advantages of clear knowledge representations, strong modularity, modifiability, and expressability. Furthermore, since most production systems integrate the abstract specifications and the procedural computations into a single system, the special-purpose compiler which is used to facilitate the automation of communication protocol implementation is no longer required between the specification phase and the implementation phase. By combining the production systems with the RETE pattern matching algorithm and a parallel multiprocessor machine like the Encore Multimax, the proposed PDPS can achieve a remarkable performance in parallel execution.