Abstract: The methods of damage state detection and fault diagnosis of wind turbine blades were reviewed, and the research status and problems worthy of study were pointed out. The fault types and corresponding fault mechanism of wind turbine blades, several commonly used methods of state detection and fault diagnosis of wind turbine blades were summarized. The advantages and disadvantages of various detection techniques were analyzed. It is found that all kinds of damage detection technology can effectively detect defects in wind turbine blades, but single detection technology has been unable to meet the requirements of blade damage fault detection. Therefore, a variety of detection techniques can be used to conduct comprehensive detection of the blade.