Abstract: In parallel computational fluid dynamics （ CFD ） applications with multi-block structured grids , to exploit fully the available resources of CPUs and / or memories for parallel computing platform , it is a common approach to repartition the original grids to obtain more sub-blocks , each with smaller volume.Two strategies of grid repartitioning are proposed for multi-block structured grids CFD application in this paper based on the investigation of existing approaches.Furthermore , a software tool named TH-MeshSplit is developed to facilitate the process of grid repartitioning , in which a simple heuristic strategy is used to solve the combinatorial optimization for the optimal splitting and yield a near-optimal solution for the problem.TH-MeshSplit can run in three modes : fully-automatic mode , half-automatic mode and manual mode , which provides user the freedom of choices and shows a good flexibility of the tool.Some numerical experiment results were reported.By evaluating the quality of grids according to several criteria , it is shown that a resulting grid with high quality can be achieved after the repartitioning and it thus confirms the validity of our grid repartitioning approach.