Seas are the most important and unexplored and unknown ecosystems and the largest source of biodiversity on earth, which make up 90% of the biosphere. Therefore, it is necessary to preserve the marine environment as a precious asset and heritage against the damages caused by human activities, including international shipping. One of the international means to achieve this aim is the port state control (PSC) mechanism, PSC which is rooted in the traditional principle of free access of ships to the ports, also international conventions and regional memorandum of understandings (MoU’s) is considered complementary to the competencies of the flag state for environmental protection and maritime safety, allows the port states to assess the compliance of ships with relevant international and regional regulations, and to carry out a non-discriminatory inspection of foreign ships entering their ports. This paper review and criticize the role of current PSC mechanisms in the protection of the marine environment. To that end, use of the descriptive-analytical method to explaining the concept and legal foundations of PSC and the most important environmental challenges caused by the Increasing growth of international shipping and analyze the role of PSC. This study's findings provide that, the international PSC regime suffers some defects, accordingly to be more effective needs to mutation, in a way that includes new environmental damages, as well as, increase international convergence and integration in its Implementation this goal is achieved through the conclusion of a global MoU
