According to a currently developing tendency towards ship design, ship will become bigger and speedier owing to the advancement of materials and manufacture technical. As a result, the working conditions of the propulsion shafting system are as different from what they used to be. The calculating specification of the propulsion shafting system contained in the Rules of the Classification Society is to be modified due to the completion of actuality practice. In this article, the evolution of the propulsion shafting system is based on the history of the Rules of the Classification Societies.