Through the study of precedent researches, this study classified the influential factors of knowledge sharing intention into the support of CEO, self-worth, trust, and incentive. Then, this study conducted a survey among the workers, who are in maritime and port sectors, to illuminate how the forementioned variables influence on the knowledge sharing intention and the usage of knowledge management system The analysis of the result illustrated that the support of CEO, self-worth, trust appeared to be the influential factors of knowledge sharing intention, and that incentive and the knowledge sharing intention appeared to influence the usage of knowledge management system. This study aims to contribute to proposing a successful forthcoming implementation of a knowledge management system, by suggesting the influential factors to increase its usage to the maritime and port organizations planning to implement it before they actually installs it.