With the rapid development of economy,air quality has serious problems,so the clean energy-natural gas is the most suitable alternative vehicle fuel.The natural gas from distribution station or pipeline got through pressure regulator, flow measurement, dewatering and drying,then was pressurized to 20 MPa in the compressor,the pressurized gas was directly inflatabled for the CNG cylinders truck transportation, and provided natural gas for CNG filling station.Through these mesures, the problem of environmental pollution was eased to a certain extent. Process design of the main process of compressed natural gas filling station,pressure relief protection process,odorization process，the selection of the main equipments including compressor and dehydration plant the selection of the automatic instruments etc., were described.