Abstract: Tahe Oilfield is a high hydrogen sulfide oilfield, the H₂S mass fraction in mixed hydrocarbon is 0.68% and the organic sulfur mass fraction is 0.22%. Current desulfurization process adopting the caustic washing process which has high treatment cost and the waste caustic washing water was difficult to treat. A novel idea of mixed hydrocarbon fractionation desulfurization process was put forward by analyzing the on-site process, the sulfur form and the physical properties in mixed hydrocarbon were analyzed. After fractional treatment, the H₂S and part mercaptan in mixed hydrocarbon entered into the natural gas processing system followed with the overhead gas. The total sulfur content in light hydrocarbons in the bottom of the tower was reduced from 0.90% to 0.15%. For further caustic washing treatment, the total sulfur content meets the requirement of GB 9053-2013 Stable Light Hydrocarbon. The alkali consumption of fractionation desulfurization process was reduced from 2 t/d to 0.22 t/d compared to caustic washing process, the dosage of alkali(NaOH) were only about one tenth of the present. The processing cost will be reduced by 1.901 million RMB per year.