The spherical cylinder coupling is the key connection device between sand roller and hydraulic motor of beach- cleaner. To study the fatigue life of spherical cylinder coupling of sand roller,firstly,the fatigue calculation with L- P theory of point connection carried out,the numerical analysis model of coupling with finite element method is built and the multi- body contact finite element analysis with augmented Lagrange algorithm is completed. Then,the cylinder load spectrum is obtained through kinematics analysis with Impact function in ADAMS. The fatigue life is analyzed based on the Miner theory in Fatigue Tool. The results demonstrate that the finite element calculation is consistent with theoretical calculation. The spherical cylinder coupling can satisfy the design requirements. The result proved the rationality of theoretical calculation. A basis for other coupling fatigue life research and simulation in the later is provided.