Ultrasonic echo Ascan method is adopted to scan large curvature carbon fiber reinforced composites and locate the defects areas. The results of metallographic microscopic analyses, thickness measuring and component surface conditions between healthy area and defect area are compared to investigate the relationships between the micromorphology of defects and ultrasonic pulse wave characteristics, as well as the causes of the defects. The delamination, air hole, and volume porosity in defect area result in poor resin in surface, thickening of the component and special ultrasonic propagation and attenuation. The defects located in large curvature position are closely related to the manufacturing process.