Abstract: Excessive oxygen content in the process of hydrogen liquefaction will lead to the accumulation of solid oxygen and the risk of hydrogen-oxygen explosion. These explosion incidents caused by such accumulations are introduced, and the importance of preventing solid oxygen accumulation is emphasized. The recent research achievements in preventing solid oxygen accumulation are reviewed, including the use of ultrapure hydrogen as feed gas, the addition of solid oxygen scrubbers, and the adjustment of solid oxygen accumulation to solid air accumulation. These methods may increase costs or energy consumption. A new solution to prevent the accumulation of solid oxygen and safely eliminate it by installing two throttle valves is proposed. Meanwhile, the process simulation validates that supercooled liquid hydrogen may be obtained more easily by the optimized process. The optimized process is suitable for a wide range of hydrogen liquefaction plants without additional equipment or increased energy consumption in practical applications.