Abstract: Compared with the storage tanks put into operation synchronously with the LNG terminal, the pre-cooling process for the expanded storage tank varies greatly. As few studies were carried out on the pre-cooling scheme for storage tank expansion, the differences between storage tank expansion projects and new projects were analyzed with reference to the process flow of the terminal based on the storage tank expansion project of a large coastal LNG terminal. Meanwhile, the adaptability of 4 LNG filling methods was analyzed, and the pre-cooling scheme was designed for the expanded storage tanks, thereby forming the key procedure and process indicators of pre-cooling, including the pre-cooling of the LNG discharge pipeline, filling of the LNG discharge pipeline, nitrogen replacement, pre-cooling of the storage tank, storage tank filling and standing, and the pre-cooled filling of low-pressure export pipeline and emptying pipeline. The case application results of the project show that the designed scheme is easy to operate in process, the cooling rate of the storage tank and the pipeline is as specified in the standard, and the good effect of pre-cooling is realized. The pre-cooling scheme is generally applicable to the subsequent storage tank expansion projects, which could provide a reference for the preparation of the pre-cooling scheme, the on-site precooling operation, and the selection of key process indicators.