A Liquefied Natural Gas(LNG) terminal uses tank trucks for transporting liquid nitrogen from the air separation plant, a method fraught with issues such as lengthy time consumption, short operating hours, susceptibility to leaks, non-standardized operations, and various factors compromising timely delivery. In response to the above, through investigation and analysis of the factors affecting the liquid nitrogen supply, a new liquid nitrogen direct supply system was chosen as the optimal solution. The results show that: the system significantly accelerates the liquid nitrogen filling process, reducing the response time from 48 hours to 8 hours. The short operating hours are extended by 12 hours, enabling around-the-clock liquid nitrogen handling. The main task is done by Distributed Control System(DCS) operators, saving 160 man-hours over one year. It can save 200 000 yuan of liquid nitrogen cost over one year(including the intermediary cost and transportation cost of tank trucks). This pioneering modification and application of the new liquid nitrogen supply system sets a precedent nationwide. It offers a new process flow scheme and replicable template for nitrogen supply at domestic LNG terminals, substantially cutting operating costs and mitigating nitrogen supply risks.