In order to increase output of liquefied petroleum gas (LPG), it is necessary to analyze, study and improve technological process of liquefied petroleum gas. Analyzed are effects of fractionating system technological parameters and cryogenic temperature reduction on liquefied petroleum gas (LPG) production through using HYSYS software simulation. Adjusted are technological parameters of the fractionating system according to the simulation results, comprehensively considered is adaptability of associated equipment and units and increased is the concentration of ethylene glycol lean liquid. Results show that the cryogenic temperature downstream of the J-T valve can he reduced down to -27°C and LPG output can increase by 24t/d if ethylene glycol unit injection quantity meets relative requirements. Application of HYSYS software simulation in LPG output increase has obtained obvious effects.