Liquid Natural Gas (LNS) is the clean energy which is the fastest growing energy in the world and is increasingly used in China. LNG leakage would induce to a nasty accident during its storage. To assure the production and application of the clean energy, the studies on the LNG leakage are of great importance. The leakage model and the damage after LNG disperses have been widely researched. Fault Tree Analysis (FTA) is a method with causal and logical relation indicating all kinds of factors causing danger. It has advantages of intuition, comprehension, and efficiency, etc. Systematical studies on LNG leakage using FTA are short up to now. Based on FTA, the factors causing LNG leakage were systematically analyzed. The order of factors influencing LNG leakage accidents was quantitatively determined. It indicates that the tank, the pipeline and man-made factors are the mainly reasons for the leakage. In order to prevent the above mentioned phenomena, the reliable theory evidence involving accuracy of safety countermeasures is provided for improving the level of safety operation, ensuring the safety of LNG storage and the reliability of operation.