This paper comprehensively analyzes the role of China's Coast Guard in maritime territorial disputes and the strengthening of China's Coast Guard, focusing on the fact that the state's major actors for the protection of maritime sovereignty have changed from the navy to the coast guard. In addition to the expansion of quantitative force, China is also strengthening the Coast Guard's qualitative capabilities, such as reorganizing its chain of command and establishing a legal foundation for mission. Taking advantage of the strategic flexibility and economic feasibility of the Coast Guard, China is expanding its maritime claims in the South China Sea. China will continue its strategy to manage the level of conflict regarding maritime territorial dispute by using the Coast Guard, and to solidify its jurisdiction claim by constantly deploying Coast Guard forces that overwhelm neighboring countries.