Jetty structure, a kind of offshore structure installed in offshores or oceans less than 50 m deep, is used for berthing and mooring of ships to unload the ship`s cargo, mainly coal and oil. The major differences compared with structures constructed in land are existing due to the effects of waves, winds, currents and the impact loadings from ships. The basic design of jetty structures has been carried out by the experience-oriented process that heavily depends on the designer`s knowledge and decision. In this study, a prototype of expert system for basic design of jetty structures was developed by employing Smart Elements, a commercial expert system shell, on a personal computer environment. The developed system determines the global jetty structure design and each jacket structure design composing the jetty. In order to develop the expert system, examination of pre-designed drawings of jetty structures and construction of databases for fenders, pipes, materials and design factors were carried out. In addition, comparison of designed results obtained from the developed system and pre-designed drawing used for existing construction was made for verification of the developed expert system.