With the continuous increase of China’s imported LNG, some large-scale LNG receiving terminals in China have begun to be expanded to improve their gasification and transportation capacity. Therefore, how to ensure the operation reliability of the new equipment, especially high-pressure pumps, to reach the expected efficiency and capacity has become an important research topic on LNG receiving terminals. In this paper, the technical problems arising from parallel operation of multiple high-pressure pumps were sorted out based on the data of four years' successful operation of the phase II project of the PetroChina Tangshan LNG receiving terminal. Then, the causes of these problems were analyzed according to design data, pipeline layout and interlock protection logic, and the main factors influencing the flow rate distribution between multiple high-pressure pumps were determined. Finally, the measures for optimizing and improving the related operation modes and technological process were proposed. And the following research results were obtained. First, the π-bend structure of the inlet and outlet header is the reason for the difficult liquid pumping and discharge in some high-pressure pumps. Second, the opening of the outlet valve is an important factor affecting the sudden change of flow rate distribution. Third, LNG backflow in the high-pressure output header is the direct reason for the phenomenon that the outlet flow rate of the high-pressure pump is occupied rapidly. Fourth, the connection between the high-pressure pump well and the gas phase space of recondenser is the main reason for the fluctuation of the liquid level in the high-pressure pump well. Fifth, 4 measures for operation optimization are proposed. First, give priority to starting the high-pressure pump at the distant end of the high-pressure output header; Second, keep the opening of the outlet valve of the high-pressure pump at a higher level; Third, empty the in-service pump well to storage tank process to avoid the risk of BOG accumulation in the pump well; Fourth, check the operating state of the outlet check valve of the high-pressure pump regularly. In conclusion, the proposed optimization method is effective and reliable, and it ensures the maximum gasification capacity of 4 200×104 m3/d at the Tangshan LNG receiving terminal. The research results provide technical reference for the expansion of existing LNG receiving terminals and the construction of new receiving terminals.