With the widespread application of underwater unmanned systems in military and civilian fields, the technical need to counter underwater unmanned systems has become increasingly urgent. This article reviews the key technologies for underwater unmanned system countermeasures, including detection, identification, interference and destruction. In addition, this article also discusses the application of multi-sensor fusion, collaborative operations and command and control systems in comprehensive countermeasures. Future research will be devoted to the development of new materials and technologies, the improvement of intelligence and automation levels, and the development of multi-platform collaborative sensing and combat technologies. Through the comprehensive application of these key technologies, the ability to counter underwater unmanned systems can be effectively improved and the safety of underwater combat platforms can be guaranteed.