In the view of the influence of different unstructured mesh types on the fluid calculation efficiency and convergence on premise of the same surface mesh size and body mesh unit number, the computational efficiency and convergence of tetrahedral mesh, hexahedral mesh and polyhedral mesh in CFD calculation are compared. The result shows that under the conditions of same surface mesh size, the convergence of hexahedral mesh is better than that of the others. Besides, the time and RAM for calculation of hexahedral mesh are less than that of the others. The convergence rate of polyhedral mesh is much better, but the computational efficiency of polyhedral mesh is a little lower than that of tetrahedral mesh. The computational efficiency and convergence of tetrahedral mesh is worse than that of the others. Under the conditions of body mesh unit number, the convergence precision of hexahedral mesh is better. The computational stability of tetrahedral mesh is better. For the convergence rate, polyhedral mesh is as well as tetrahedral mesh. Besides, the convergence precision and the computational stability of polyhedral mesh is much better. So the application range of polyhedral mesh is superior to the others in comprehensive comparison.