Various simulators are installed in a school and a training institution in marine transportation countries in the world. However, the institutions having a full mission type diesel plant simulator in a domestic education organization such as a maritime college or a university are only 1. A full mission type simulator begins to make a trouble state for training and can carry out training with a sense of reality. However, the system needs the staff of instructors to move it, and the number of people witch can train by the system at a time is limited. On this account a lot of simulators of a PC base assumed that expense is effective for introduction education and practice cheaply are introduced. We study a diesel plant simulator for education that a student uses a PC as for the authors, and self-study is enabled. By this report, We report about development of a marine diesel plant simulator which used an expert system to improve an education effect.