Abstract: Using the Romax Designer engineering analysis software to model the overall gearbox of a large MW wind turbine, a large amount of analysis and calculation were conducted on the contact stress, modification effect, and bearing life of the cylindrical roller bearing of the gearbox output shaft under different relative inclinations of the inner and outer rings according to the classic rolling bearing theory and the basic idea of the "slicing method". The focus is on analyzing the ISO/TS 16281 lifespan of bearings, analyzing the impact of the inclination of the inner ring relative to the outer ring on the ISO/TS 16281 lifespan, and the impact on the lifespan of bearings under the optimal convex measurement of unmodified and logarithmic modification. The ISO 281 lifespan and ISO/TS 16281 lifespan are also compared. The research results indicate that regardless of whether the bearing is modified or not, the inclination of the inner ring relative to the outer ring has a significant impact on the ISO/TS 16281 lifespan of the bearing. Moreover, the larger the inclination, the shorter the service life of ISO/TS 16281, and the larger the corresponding optimal modification convex magnitude, the better the corresponding modification effect, and the greater the increase in the rated service life of ISO/TS 16281:2008. Under the same relative inclination of the inner and outer rings, the lifespan of ISO/TS 16281 differs significantly from that of ISO 281. The research results can provide reference for the optimization design of cylindrical roller bearings.