Automotive engine valves are subject to various stresses from such loads as combustion pressure and spring load, thermal loads and valve impact closing velocity. They interact with each other and sometimes lead to valve fatigue fractures. In this paper, finite element methods were extensively used to study valve stress behavior under various loads from durability test cycles. A 3D nonlinear thermal-mechanical model was constructed and the implicit time integration method was employed in valve transient dynamics under closing event. And, Head thermal deformation was considered. These stress results obtained from FEM were in good agreement with measured data under valve train rig test and the real crack position on the valve neck was simulated.