The dissertation is a study of the environment constraints, which may be createdfrom Sihanoukville Port development in Cambodia. This dissertation can be used as a fundamental guide for evaluation of the degree and level of pollution, in order to prevent, reduce and control of pollution resulting from port location, port construction and port operation. It consists of seven chapters connecting to the development of Sihanoukville Port and the environmental considerations from this development. Firstly, the author will addresses the historical background including the socioeconomic situation and natural resources condition in the Kingdom of Cambodia, and the port and transportation network and its development. Secondly, there will also be discussed of the impacts of port location, port construction and port operation on the natural resources, water, air and soil quality by the construction material, shipping activities and cargo handling in the port. In this dissertation, the author will also review of the international and national instruments which are related to the prevention and mitigation of environmental pollution from port construction and port activities and will also focus on how to implement them. In addition, the author will also address the policy of the government and the roles and responsibilities of the Ministry of Environment regarding to the development of the Sihanoukville Port Development Project. Finally, the concluding chapter will evaluate the degree of environment constraints from the development of Sihanoukville Port and how the constraints can be mitigated if the project comply with national and international instruments. A number of recommendations are made to prevent and reduce pollution from Sihanoukville Port development.