Abstract: A gas chromatographic system with 7 columns, 5 valves and 3 detectors was established, and it was applied to the simultaneous ultimate and determination of determine components of imported natural gas. The proposed method was applied to the analysis of standard sample and substantial samples of natural gas. In the analysis of a standard sample of natural gas, relative errors ranged from -0.015% to 0.020% as referring to the certified values, were obtained. Values of RSD′s (n=5) found from the results of analysis of substantial samples were in the range of 0.020% to 22%.