The invention discloses a space-division system for highly effectively using cold energy of liquefied natural gas (LNG), comprising an LNG-nitrogen heat exchanger and a nitrogen-nitrogen heat exchanger. The pressure nitrogen is used as the closed circulating medium. The liquefied natural gas transfers the cold energy to the circulating nitrogen in the LNG-nitrogen heat exchanger. The circulating nitrogen transfers the cold energy to the pressure nitrogen of a space-division rectification tower in the nitrogen-nitrogen heat exchanger. The space division is not in contact with the circulating medium directly so as to avoid the danger caused by the natural gas entering a space-division device. The circulating nitrogen is cooled by the LNG cold energy so as to reduce the compression power consumption and obtain super-critical pressure nitrogen. In order to make up the disadvantage of the high-grade cold energy of LNG, one path of the high-pressure liquid nitrogen is throttled to the intermediate-pressure pressure, another path of the high-pressure liquid nitrogen is expanded by an expander to recover energy and then partially enters the LNG-nitrogen heat exchanger for deeply superbly cooling the high-pressure liquid nitrogen, and the rest liquid nitrogen enters the space-division system. The number of the channels of the heat exchanger is seldom, the flow organization is simple, safe and reliable, the operation and control are simple, the cost is low, and the application range is wide.