Abstract: Ship ballast water is one of the main ways for the alien invasion. It is considered as one of the four threats to the marine environment. The ballast water convention established to solve this problem has stipulated the standards for ballast water treatment， which has entered into force on September 6，2019. This paper reviews the background and social needs of the research on ballast water treatment technology， analyzes the characteristics of different ballast water treatment technologies， introduces the latest achievements of the research on ballast water treatment technology in the academic community， and the efforts of the industrial community in the research and development of ballast water treatment systems， and discusses the challenges faced by ballast water treatment at different levels of standards， economy， technology， testing and law.

Key words: oceangoing vessel, ballast water treatment technology； ballast water convention