The liquid adsorption separation of n-paraffins in naphtha with n-pentane as the desorbent was investigated and the subsequent recycle of n-pentane was simulated by Aspen Plus. The optimal operation conditions for both the adsorption and desorption processes were studied. Then n-pentane was recycled by simulated rectification; the raffinate bottom oil rich in non-normal hydrocarbons and the desorption bottom oil rich in normal hydrocarbons were obtained. As compared to the naphtha before the adsorption-recycle process, the ethylene yield would rise by 15.76% by employing the desorption bottom oil as the feed for the ethylene cracking process and the octane number of the raffinate bottom oil would rise by 20 units.