Abstract: In the study, the new technique of hydrocarbon condensation on capillary column was mainly applied, with the quartz inner tube of the injector in chromatographic analyser as sample tube. Residual hydrocarbon C₅-C₃₅ in rock samples were expelled by carrier gas in pneumatolytic chamber at controlled temperature (250℃), which condensated on the head of capillary column, and then programme temperature started for chromatographic analysis. Tests show that the chromatographs and data obtained by the method are practical in identifying oil, gas, and water formations. Meanwhile the method would be used in whole hydroearbon (C₅-C₃₅) analysis.