Mesh is the foundation of computational fluid dynamics (CFD) numerical simulation. To investigate the applicability of different mesh types to gas dispersion simulation in chemical industrial parks, full-scale numerical simulations were carried out based on field leakage experiments of tracer gas (SF6) conducted in a typical chemical industrial park. Four mesh types were selected: tetrahedral, polyhedral, hybrid tetrahedral, and hybrid polyhedral, and a comparative study of the meshes was conducted in terms of meshing characteristics (quantity, orthogonal quality, aspect ratio) and CFD simulation performance (solution precision, accuracy, and computational time). The results show that in terms of meshing characteristics, polyhedral meshes have the fewest cells (0.6-1.5 million), followed by hybrid polyhedral meshes (0.8-3.3 million); the orthogonal quality of hybrid polyhedral (0.44) and polyhedral (0.41) meshes is significantly better than that of tetrahedral (0.04) and hybrid tetrahedral (0.02) meshes; hybrid polyhedral meshes have the lowest aspect ratio. In terms of simulation performance, hybrid polyhedral meshes achieve the highest computational precision, reaching 10^{-4}, they have the smallest error between simulated and monitored values and the best correlation (0.98), simultaneously, their simulation efficiency (27 min) is significantly higher than that of polyhedral (47 min) and hybrid tetrahedral meshes (112 min). Furthermore, from the perspective of flow field characteristics, plume width from polyhedral meshes is greater than that from hybrid meshes, and hybrid tetrahedral meshes yield the highest average plume concentration.