This study firstly reviewed the kinds and features of oil major inspection and also investigated the recognition of their 5 working groups who are 4 ship management fields such as technical affairs, operation affairs, crew affairs and safety & quality affairs of tanker shipping companies and oil major inspector related to oil major inspection works activity. This thesis examined the impact of oil major inspection on the safety of ship operation. The data were collected from 86 employees engaging in 4 ship management affairs working groups in 6 tanker shipping companies and 3 tanker ship management companies in Busan and Seoul. As for the recognition of oil major inspector groups, they responded that the performance and maintenance of oil major inspection is highly related with the securing safety of ship operation, and also the system has an highly positive impact on the securing safety of ship operation. In addition, those people who are engaged in four ship management affairs groups of tanker shipping companies also responded that oil major inspection performance and maintenance is deeply related with the securing safety of ship operation and the system has an positive impact on the securing safety of operation.