Combined experimental and numerical studies are conducted to study ice storage performance of an ice storage tank with finned tube. Axially arranged fins on the refrigerant tube are applied to enhance the solidification. The evolution of the solid−liquid interface and the variation of temperature of the typical position is examined. The effect of natural convection is discussed in detail. In addition, the effects of refrigerant temperature and initial water temperature on the ice storage performance are analyzed. The results indicate that the ice storage performance is enhanced by the metal fins remarkably. The defection of poor heat transfer after ice is formed can be solved by applying fins in ice storage devices. Natural convection leads to unnecessary mixing of water with different temperatures, lessening the cooling energy stored and acting as a disadvantage during solidification. Decreasing the refrigerant temperature and initial water temperature is beneficial for ice storage.