The accumulation of micro-damage such as matrix crack and fiber fracture in carbon fiber reinforced polymer (CFRP) under cyclic loading will seriously affect the mechanical properties of CFRP.The size of micro-damage is small and the locations of micro-damage are scattered,which are difficult to be accurately identified by traditional nondestructive testing methods.Laser ultrasonic detection technology has the advantages of non-contact,fast detection speed,wide measurement range,et al.Especially combined with the advantages of laser long distance excitation and large angle incidence,it has a great potential in the damage detection of large size and curved structure materials.Based on the thermoelastic effect of laser,the generation process and propagation characteristics of ultrasonic wave in CFRP are systematically studied on the basis of analyzing the distribution of temperature,stress and displacement field after laser is applied to CFRP.Through the analysis and comparison of ultrasonic echo signals with defects in different places in CFRP,the corresponding relationship between defect position and echo signal characteristics is obtained,so as to realize the reverse performance of the key information of defect position in CFRP from the echo signal characteristics.