Natural surfaces with super hydrophobic properties often have micro or hierarchical structures.In this study,the wetting behaviors of a single droplet on the surfaces patterned with micro square-posts and hierarchical structures with different geometrical parameters are investigated numerically using lattice Boltzmann method(LBM).LBM is a mesoscopic method,and can model the interfacial dynamics of multiphase flow by incorporating intermolecular interactions at mesoscopic level.In addition,the boundary treatment in LBM is very simple and costs little in computational resource.These features make the LBM to be very useful for simulating flows with complex boundaries.An improved lattice Boltzmann method for modelling and simulation of droplet dynamics on both chemically heterogeneous and micro structured partial wetting surfaces is developed and reported firstly.Applying the improved method,the effects of surface chemistry and topography on motions of liquid drops are studied and analysed numerically.The obtained steady contact angles are in good agreement with those of theoretical prediction.Moreover,based on the evolutions of phase distribution and flow fields obtained from the numerical calculation,the corresponding mechanisms of droplet dynamics on the micro structured surfaces including droplet spreading,migration as well as dynamic apparent contact angle etc.are discussed and analysed.