Abstract: Cylindrical Roller bearing of an engine failed during use, one side of the roller occurs spalling, and the inner raceway is squeezed and worn. Carried out the analysis of the fault morphology, the bearing review, the measurement of the tilted angle of the inner ring and the outer ring, the bearing anti-tilted angle calculation and the contact stress calculation. The results show that the bearing has a large tilted angle during the working process, and the roller profile is in contact with the edge of the inner raceway, resulting in stress concentration, causing the roller to spalling and the inner ring raceway to press and wear. Improved measures to increase the raceway length and the roller convexity to prevent edge contact, reduce contact stress, and prevent such failures.