Abstract: In view of the particularity of wind turbine blade FRP composites, infrared continuous thermal excitation nondestructive testing technology is used. The infrared image is enhanced by Fourier transform and contrast-limited adaptive histogram equalization (CLAHE). Firstly, the temperature sequence composed of consecutive multiple infrared heat maps is fast Fourier transformed, and the phase information is extracted to obtain the phase map. On this basis, the best phase map is selected and processed by CLAHE algorithm to improve the global contrast of the image. The experimental results show that the contrast to noise ratio (CNR) of infrared images is higher than other traditional methods after enhanced processing, which shows the effectiveness of the processing method. At the same time, the infrared image of the fan blade is collected and verified. This method is effective and accurate. The ability to identify infrared thermal imaging defects of wind turbine blades is improved.