Abstract: Torpedo is one of the main threats for surface ships. Great efforts are being made to develop effective torpedo defence systems to protect their vulnerable surface ships from the growing underwater threat for navies worldwide. Successful defence against modern torpedoes' attack requires an automated, fully integrated, layered defence system. With the proliferation of weapons and the accompanying diversity of capability, defensive capabilities have needed to become robust against a wide range of weapons within the diverse operational environments. The naval requirements, basic system components, torpedo warning, countermeasure options, layered torpedo engagement et al. are discussed, which are closely related to how to design an effective surface ship torpedo defence system.