Abstract: With the great improvement in computer technology and numerical methods, computational fluid dynamics has progressed significantly. Even though it is easy and fast to obtain discretized results via numerical simulations, the validity and accuracy of the results need to be carefully verified and validated. Grid convergence study is one of the important approaches in verification process; however, traditional methods cannot realize consistent refinement on general unstructured grids, causing difficulties in grid convergence study on general unstructured grids. In order to solve this problem, the downscaling accuracy testing method (DS method) was adopted in this paper. The DS method was successfully verified by comparing with traditional mesh refinement method and analytical stencil analysis for three cases:a) gradient reconstruction accuracy on isotropic grids; b) gradient reconstructure accuracy on anisotropic grids; c) flow simulation accuracy of a manufactured solution on isotropic grids. The DS method was implemented for accuracy tests on anisotropic stretched grids commonly used in the simulation of viscous flows, and the results were consistent with predictions, which demonstrate the advantage of the DS method on accuracy verification with general unstructured grids.