Micro-structure of porous medium that approximates natural porous medium is generated stochastically by numerical method.Numerical simulation of gas diffusion in porous media is implemented with LTRT lattice Boltzmann method to investigate the effects of pore characteristics on diffusion process.It is demonstrated that diffusion processes are quite different in different porous micro-structures with the same porosity.The results also show that the dimension of the width of channels influences the diffusion.The diffusion rates increase as the channel width increases.The effect resulted from the variation of channel width and porosity in the diffusion process is far less than that for different pore structures.The influence caused by the variation of radii of filleted corners is little.These explorations provide theoretical basis and statistical support for the generation of porous media and the design and optimization of the pore characteristics of micro-reactor.