Abstract: A fixed bolt on a low pressure turbine disk of an aero-engine fractured. Macroscopic observation, fracture analysis, metallographic examination and chemical composition analysis of the fractured bolt were carried out. The results show that the reason for bolt fracture was that the oblique tensile stress was generated during assembly, and the grain structure was coarse, which reduced the plasticity and impact toughness of the material, and reduced the overall bearing capacity of the bolt.