Abstract: During the service of an aircraft, failure occurred to the two-row cylindrical roller bearing of horizontal hinge of main propeller hub. The failure modes are mainly fracture and raceway spalling of the inner ring. Through morphology analysis, review and calculation, it was found that the failure was mainly caused by bending deformation of the inner ring of the bearing under working condition. On the one hand, there was larger stress at inner diameter of inner ring end face, resulting in the fracture of the inner ring. On the other hand, edge stress was generated at the bearing raceway, leading to raceway spalling. The improvement measures are as follows: adding 3 inner diameter groovers at inner diameter of the inner ring, and modifying roller busbar and the raceways of inner and outer rings. The improved bearing passed two sets of 600 h durability test. The results show that the above improvement measures can help to prevent such failure of the bearings.