A study of molecular dynamic simulation was conducted to investigate dif- fusion characteristics of the guest molecules which diffuse into uni-directional zeolitic structures. Because of the complex and narrow micro-pore structures the zeolites possess, the observation of the anomalous diffusion behavior was reported. Especially, single file diffusion occurs when the zeolites have a un- connected narrow single channel, which hinders the mutual passage of guest molecules. In this research, the diffusion behavior of the mixture consists of CO2 and N2 in the zeolites of TON, AFI, and LTL which have a unconnected single channel has been investigated. The effects of the pore size and length variations on the diffusion behavior were elucidated. Finally, the change of diffusion behavior for TON anchored with the functional group selected as the ammonia was also investigated.