In order to estimate the impact damage of composite materials,the infrared imaging method based on hot wind heating is proposed.Firstly,the background difference is carried out for infrared images of composite materials.Then,all difference images are added to enhance SNR.At last,the threshold segmentation is adopted for binarization processing of the image,and then the position of the impact damage is segmented.The experiment results show that,this method has many advantages,for example,simple equipment,easily seen result and so on.This method can be applied for the damage detection in aerospace composite materials.