Abstract: The paper analyzes and summarizes typical defects causes of wind turbine blade by the literature research.In the process of production,installation and operation,it is possible to produce defects and damage.The occurrence of the accident can be prevented and avoided through a combination of test and monitoring.At present,there is a lack of relatively perfect solution for the defect and damage detection of wind turbine blades domestically.By combining with the development of wind power industry and through the comparison and evaluation of various nondestructive testing methods,the following conclusions might be drawn that Ultrasonic testing technology is suitable for static test of the blade before installation,Infrared thermal imaging technology is applied to field detection of the blade and acoustic emission testing technology is applicable to dynamic monitoring of blade under the service process.