Abstract: The rotating bending fatigue tests of tellurium modified C70S6 non-quenched and tempered steel were carried out by fluctuation method and group method. The rotating bending fatigue properties of the samples were studied, and the mechanism of tellurium modification was analyzed. The results show that under confidence of 95% and the failure probabilities of 10%, 50%, the fatigue strengths of the test steel according to the fluctuation method were 385.0, 458.8 MPa, and according to the group method were 379.9, 432.0 MPa, respectively. The fatigue strengths obtained by the two methods were all higher than enterprise requirements and than those of C70S6 non-quenched and tempered steel without tellurium modification. The sulfides in the test steel were MnS and Mn(S, Te), most of them were ellipsoids with small curvature radiuses, and the grading results were fine series 1.5 and coarse series 2.0, The sizes of the sulfides were smaller than those of the domestic C70S6 non-quenched and tempered steel without tellurium modification, and was comparable to those of the foreign C70S6 non-quenched and tempered steel without tellurium modification. Tellurium modification improved the rotating bending fatigue properties of C70S6 non-quenched and tempered steel by adjusting the forms of sulfides and reducing the sizes of sulfides.