The Caspian Sea has become one of the most important strategic areas of the world in recent years. However, human activities and abnormal exploitation and the large annual inflows of pollutants are serious threats to its ecosystem. In the present study, strengths, weaknesses, opportunities and threats are used for transboundary diagnostic analyses by SWOT strategic planning model. Eight strength points, four points of weakness, five opportunities and five threats were identified and 10 appropriate and practical strategies were presented and internal and external factors values were set at 37.38% and 35.18%, respectively. The result strongly emphasis on the compilation of strategic environmental plans for the control of oil, BOD, phosphate and nitrogen pollutants of neighboring countries, especially. The most important strategies include the formulation of common standards, indicators and guidelines on environmental quality and water quality in the Caspian Sea is required. In conclusion, it should be highlighted that the following legal regime may decrease the environmental problems of the Caspian Sea.