Abstract: An introduction is made on the theory of three-dimensional CT imaging, and a reconstruction algorithm for the abnormal structure such as aero-engine turbine blade is given. Researches on the three-dimensional CT gas turbine engine test were carried out. Results show that the 3D industrial CT technology can characterize the internal cracks, such as porosity, inclusions and other defects from multiple azimuths, resulting in more direct and more complete viewing of the defects than film radiography, and is worthy of promotion.