Abstract: With a case study of expanding L-CNG filling facilities in a filling station in Guangdong, this paper presents the CNG storage in filling stations in two forms, i.e. storage well and cylinder group, in aspect of operating principle, structural composition, and construction/assembling flow. Through comparative analysis on both storage forms in terms of safety, floor space, verification and detection, service life, construction difficulty, construction cost and removability, this paper reveals that the CNG storage well is more safe, with small floor space, whereas the CNG cylinder group can be easily constructed in a shorter period and it is also removable. Therefore, storage well is recommended when the L-CNG facilities are expanded in a filling station. Additionally, this paper points out some considerations for L-CNG storage well.