Abstract: DHX light hydrocarbon recovery process often add deethanizer reflux system in order to improve the yield of light hydrocarbon. Based on the actual parameters such as gas components and pressure in light hydrocarbon recovery plant of Tarim, on the basis of reasonably determining the boundary conditions, the HYSYS software was used to analyze theoretically the four possible operating modes of DHX light hydrocarbon recovery process. It was concluded through the contrast analysis that (1) the scheme of J-T valve + reflux pump operation mode was infeasible; (2) Under the mode of expander refrigeration, the reflux at the top of the deethanizer could significantly increase the propane yield and reduce the circulation volume of the F line by 43%. For large equipment, the design size of the deethanizer, DHX tower and shielding pump could be significantly reduced to decrease the equipment investment and manufacturing difficulty; (3) The temperature of F line out of the cold box had a great influence on circulation rate. Under the refrigeration mode of J-T valve, the temperature of F line out of the cold box should be controlled as far as possible at a higher value to avoid low pump flow of DHX tower bottom; Under the mode of expander refrigeration, in order to avoid DHX bottom overload operation, the exorbitant temperature of F line out of the cold box was unsuitable; (4) Under the mode of expander refrigeration, when temperature of line F out of the cold box was too low, the circulating amount of absorbent at the top of DHX tower dropped below the minimum circulating amount, and the propane yield of the device dropped rapidly; (5) In order to make the propane yield of the device reaching the advanced level of above 98%, the temperature of the reflux tank should not be higher than -31 ℃.