Recently, the navigation risk is increasing significantly with growing of vessels' volume and propelling marine facilities, water bridges and port development etc. As a result, Ministry of Land, Transport and Maritime Affairs enacted a new law called MSA(Maritime Safety Audit) as a comprehensive maritime traffic safety management scheme in order to ensure safety improvements from the early planning stage to post managing of the development which affect the maritime traffic environment. MSA as a tool for improving maritime traffic safety is a formal safety diagnosis assessment in the existing or future ship's fairway by an independent audit institute. It examines the potential hazards of maritime traffic safety about the port development, if necessary, and is to ensure the implementation of appropriate safety measures. The primary purpose of MSA is to identify potential risk elements affecting safe navigation. This paper is aimed to introduce the backgrounds, the necessity and efficiency of MSA and also to describe some technical standards and diagnostic procedures.