Three-dimensional fluid seepage behaviors in porous media were studied using Lattice Boltzmann simulation. Spherical particles were used as the porous media and LBM lattice was applied to describe size and shape. Particle boundary was represented by middle points of grid lines. Moreover, interaction between fluid and particles was achieved through Link Bounce-Back. Seepage behaviors of fluids in Darcy region, transitional region and Forchheimer region were analyzed. The simulation results were compared with fundamental theory of seepage flow, which was in good agreement with experimental and MRT simulation results from literature. Furthermore, variation of flow line with Reynolds number in different regions was analyzed. Simulation results show that the flow line changes with the increase of inertial force with vortex appears in certain conditions. The vortex area increases with the increase of Re number and covers whole pore spaces at high Re numbers. Moreover, the results show that Reynolds stress increases with inertial force, and the effects of pore medium structure on Reynolds stress is reduced with the increase of inertial force. © 2018, Editorial Board of "Journal of Chemical Engineering of Chinese Universities". All right reserved.