With the vigorous development of the liquefied natural gas industry, the development of cascade utilization of cold energy of LNG technology has huge economic efficiency. The LNG technology is beneficial to lower the cost of LNG and develop the downstream market. However, at present, there is less research on the safety of LNG cold energy cascade utilization. 18 kinds of schemes for LNG cold energy cascade utilization have been designed with three-level utilization as an example based on the existing research achievements in this paper. A process of one typical cascade utilization scheme was taken as an example. At first, qualitative analysis was conducted for the potential risks involved in the preliminary risk analysis of process equipment, and then quantitative calculation and evaluation of potential risks were performed using the method of job risk analysis to determine the risk level of each equipment and put forward reasonable preventive measures and suggestions. Then weight assignment was performed according to the equipment risk score and process risk score was obtained by a given process formula of risk. An LNG cold energy cascade utilization risk calculation formula was given by the same method, providing guidance for the safety analysis of each scheme. PHA - LEC method provides a combined model of qualitative and semi- quantitative analysis for the safety analysis of LNG cold energy cascade utilization and is serving as a scientific basis for scheme optimization selection and preparation of preventive measures.