Wing-assisted navigation is one of the effective ways to realize the green development of ships.The hydraulic system is an important part of the wing propulsion system,and its operating condition determines the operational reliability and energy saving effect of the wing-assisted ship.Taking the wing hydraulic system as the object,its fault location,method,characteristics and consequences were analyzed comprehensively; the applicability of various diagnosis methods in the wing hydraulic system was also analyzed,the characteristics and deficiencies of various diagnosis methods were summarized by reviewing the fault diagnosis methods of hydraulic systems at domestic and overseas.The analysis result shows that the intelligent diagnosis method with multi-level diagnosis structure has advantages in improving the fault diagnosis accuracy of large and complex hydraulic systems and reducing the complexity of the diagnosis model.It will become the development trend of the research on ship wing hydraulic fault diagnosis.