NOVELTY - Isomerization of light hydrocarbon comprises isomerizing the light hydrocarbon material into an isomerization reactor in the front, carrying out gas-liquid separation to the fluid from outlet of the reaction in the front, separating the obtained liquid-phase fluid into a de-isohexylation column, mixing the top fluid with the bottom fluid; leading the lateral fluid of the column, carrying out gas-liquid separation, and returning all the obtained liquid-phase fluid and mixing it with the liquid-phase fluid from the gas-liquid separator of the isomerization reactor in the front.    USE - The process is useful for isomerizing light hydrocarbon (claimed).    ADVANTAGE - The process is high in n-alkane isomerization rate and the six carbon-containing n-alkane is basically isomerized completely; thus, the octane value of the light hydrocarbon material is greatly promoted.    DETAILED DESCRIPTION - Isomerization of light hydrocarbon comprises isomerizing the light hydrocarbon material into an isomerization reactor in the front, carrying out gas-liquid separation to the fluid from outlet of the reaction in the front, separating the obtained liquid-phase fluid into a de-isohexylation column, mixing the top fluid comprising five carbon-containing distillate and dimethyl six carbon-containing alkane with the bottom fluid comprising seven carbon-containing distillate and above, taking the mixture as the isomerization product de-gasoline stabilizing system; leading the lateral fluid of the column mainly comprising six carbon-containing n-alkane and monomethyl six carbon-containing alkane into the isomerization reactor at the back, carrying out gas-liquid separation to the reaction fluid in the isomerization reactor at the back, and returning all the obtained liquid-phase fluid and mixing it with the liquid-phase fluid from the gas-liquid separator of the isomerization reactor in the front as the feed stuff of the de-isohexylation column; where the light hydrocarbon material is 4-7 carbon-containing hydrocarbons.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the device used for isomerization of light hydrocarbon.