With the development of liquefied natural gas (LNG)ship types，there is a new demand for small-scale refueling.To effectively promote green and low-carbon development，it is a trend to retrofit the existing large LNG wharf to adapt to the berthing of new small LNG bunker vessels.This article proposes a retrofit method for adding a berthing pile cluster system based on the existing large butterfly-arranged LNG terminal.The space model is used to simulate the structure，analyze its force and system displacement，and verify the influence of large mooring LNG ships on the system.Finally，the article proposes a set of design processes for the structure.The wharf after retrofit can berth and refuel a variety of small LNG refueling ships or carriers，with better adaptability，safety and reliability，superior durability，short retrofit period，and low investment，which has good application value and broad promotion prospects.