Abstract: Aiming at large heat transfer temperature difference and serious mismatch of heating energy level in conventional gas fractionation process, a cascade heating method using first type absorption heat pump for gas fractionation column effluent was proposed. By the method the exergy efficiency of gas fractionation process is greatly improved through diminishing heat dissipation in the top of fractionating tower, reducing steam consumption and recovering waste heat. After revamping the gas fractionation system in a refining &chemical company in Yinchuan, the steam consumption can be reduced by 22.0%, and save the operating cost about 3.98 million Yuan annually.