Abstract: In allusion to the faults happened in the operation of the Dngz-6500/1.6 low-pressure pre-dewaterer in Jimo CNG Primary Filling Station, the paper analyzes the causes in aspects of reducing power consumption, equipment selection and running mode, key parameter selection, component maintenance and installation of supporting facility, etc., and presents some specific approaches in lowering CNG loss in the process of depressure, regeneration and automatic discharge, including to choose the semi-automatic mode or adjusting the regeneration period to guarantee the effectiveness, reasonably adjust the control parameters in regeneration temperature, adsorption time, discharge period, loading/unloading to obtain a good effectiveness in dewatering and loss reducing; launch the maintenance and care over all parts and components for pneumatic film valve, magnetic valve, Roots blower, heater and some other components in the light of their operation charaacteristics; rationally lay out the matching tube networks and data lines with the dewaterer to eliminate the interference factors in the running process of dewaterer. Relying on these measures, CNG loss of dewaterer is reduced.