The lattice Boltzmann method（LBM）is an alternative kinetic-based approach in solving various hydrodynamics systems.The LBGK（lattice Bhatnagar-Gross-Krook）model of lattice Boltzmann method，including second-order boundary condition treatment for curve geometry was used to investigate the flow around a single particle.The evolution of vortex structure was analyzed to obtain the reasonable results at both steady and unsteady flows around the single particle.The drag coefficient is a key parameter in the analysis of particle-fluid complex systems，especially，in gas-solids fluidized bed.The drag coefficient was evaluated by using the momentum-exchange method over the range from Reynolds numbers 0.1 to 200，and the results agreed well with the standard equations or the published references.Moreover，this paper gives a new drag relationship based on LBM by using the least squares curve fitting method.Computational results indicate that LBM is an accurate and robust method for drag coefficient simulation.The simulated drag coefficient is more convenient and economical than that obtained by experiment.