Based on the practical experience of a Liquefied Natural Gas (LNG) powered tug, the fuel system of small and medium-sized LNG-powered ship is analyzed in fuel storage system, fuel supply system, fuel heating system, fuel ventilation pipeline system, fuel monitoring system, and fuel safety system. The realization of flexible fuel system configuration for small and medium-sized LNG-powered ship can provide reference for the design of small and medium-sized LNG-powered ship.