Whether a ship is sub-standard or not shall be finally decided by the minimum standards laid down in international conventions or national standards having the same effects. The flag State is primarily responsible for implementing these standards as far as its own ships are concerned. And the port State shall, in the exercise of its rights under international law, take appropriate measures (including detention of ships identified as sub-standard), which are regarded as port State's supplementary role aiming at implementing these standards. The international standards are implemented by the regional co-operation in the form of the MOU(Memorandum of Understanding) on Port State Control in the Asia-Pacific Region on the ground that the PSC enforcement of only one country does not enable the eradication of sub-standard ships. Recently, EQUASIS which is an international database covering the whole world fleet change the regionalism of PSC into the globalization of PSC. However, there are many problems in Tokyo MOV and Korean PSC regime. In order to ensure the implementation of the standards laid down in international conventions and Tokyo MOU, the Korean and other country in Asia-Pacific shall settle the alienation from the actuality of the law, namely the problem of maritime administrative structure of non unifying PSC affairs.