Abstract: In this study, a series of computational fluid dynamics (CFD) simulations were performed with a 100% opening butterfly valve. Grid-adaption processes, including Y plus adaption and gradient adaption, were also applied to refine the meshes. To validate the CFD method, a series of experiments were also conducted according to the national standard of valves-test method of flow coefficient. The results show that the grid-adaption based CFD method can accurately predict the flow coefficients of valves, and the grid-adaption process can effectively improve the simulation accuracy while reducing the workload of mesh refinement.