In the past, mainly metallic and nonmetallic elements were used as indica-tors in geochemical prospecting for metallic deposits, and the experimental useof organic gases as indicators has been reported only in foreign literature inrecent years. As no such test has been carried out in China, light hydrocarbonanalytical method suitable for exploration of metallic deposits has pot yetbeen developed and tested. This paper presents a newly-developed analyticalmethod for light hydrocarbon. The sample is placed in a vacuum vessel anddecomposed with acid to release hydrocarbon gases which are then determinedby gas chromatography. Nine items(C₁-C₅)of alkyl olefin can be determined si-multaneously. The detection limit for the sample is quite low:0.1 μl/kg formethane, with detection rate 100% and relative deviation not in excess of±20%. The analyses of we than3000 samples prove this method to be re-liable. Trial survey with this method was conducted in lead-zinc deposits, golddeposits and faulted areas, where light hydtocarbon gases prove to be extensi-vely existent and form distinct anomalies. Facts show that light hydrocarbongases seem to be a good geochemical indicator which is worth further investi-gation.It is for the first time that the hydrocarbon gas survey was performed inmetallic deposits of China.