Abstract: The common defects of superalloy blades shown by radiographic negative films were analyzed, and the black and white lines and diffraction spots were also studied. The results show that the reason for the black and white lines on the radiographic films is the core discontinuity: core fracture or core dislocation. The core discontinuity may show white line, black line, or black-and-white line on the negative films as the incident direction of the beam changes. Diffraction spots are a common image for equiaxed crystal blades, and they can be distinguished by changing the voltage or the incident angle. Through analyzing the formation cause of black and white lines and diffraction spots, and distinguishing the image through the corresponding confirmation method, radiographs can be accurately determined, which can provide guidance for the radiographic inspectors to make accurate judgment.