Gas-liquid flows in/on porous structures are simulated by using of the two-phase Lattice Boltzmann method (LBM), in which the wetting boundary conditions on solid wall with complex geometry are incorporated. The complex geometry simulating the packed bed is numerically constructed by the discrete element method (DEM). It is confirmed that structure of the simulated packed bed is similar to the actual bed by comparison of wall friction factor. Next the behaviors of droplet on the porous structures are simulated with different wetting properties. For hydrophilic cases, the droplets set on the porous structure at initial stage penetrated into the porous structure as time marching on and spread in the bed. It was shown that the droplet behavior depends on the surface tension and its viscosity. From these numerical simulations, the applicability of LBM to Gas-liquid flows in/on porous structures was confirmed.