This study is designed to set up a set of ship re-inspection selection system. Based on the defects of last inspection record, this system will help to verify whether re-inspection is needed or not. To fuzzify the database of Port State Control together with Important Performance Analysis (IPA) method, a two dimension matrix is established. Furthermore, Multiple Criteria Decision Making (MCDM) method is used to solve the problems which are caused by the interactive factors and re-evaluate the defects in the IPA matrix. Therefore, the system shall be flexible and practical to adjust the scale of risk assessment with monthly defects record. The system can improve the detention record of national flag vessels as well as build up a standard for assessing seaworthiness. Preventing national flag vessels from becoming substandard and avoid substandard vessels entering into Taiwan waters and port ares is also the goal of this study.