Abstract: The decision-making guideline of process design scenario of compressed natural gas (CNG) automobile parent fuelling station is described. Take the pre-dehydration technique of gas as an example, the paper gives the process flow of CNG automobile parent fuelling station. According to the Code of GB18047-2000 (Compressed Natural Gas for Automobile Use), this paper compares and analyzes the scenario of strengthening dehydration and determination method of dehydration of natural gas. For the CNG automobile parent fuelling station, the 3 gas storage manners, small-volume steel tank, large-volume steel tank and gas storage well, are compared from the earth making-up, safety and service life and so on. Meanwhile, the constitution of necessary operating system and their functions for this kind of station is introduced.