Applying the classic rolling bearing theory and the basic idea of the "slicing method",taking the output shaft bearing of a large MW wind turbine gearbox as an example,using the Romax Designer engineering analysis software,the calculations were conducted on the internal load distribution,contact stress,equivalent dynamic load of the ring and raceway,and life of the cylindrical roller bearing under different radial clearances.The effect of radial clearance on the service life of bearing ISO/TS 16281 was analyzed.The results indicate that the radial clearance not only affects the lifespan of the bearing by affecting the internal load distribution,contact stress,and equivalent dynamic load of the ring raceway,but also by influencing factors such as the life correction coefficient.The research results can provide reference for the optimization design of roller bearings.