Aiming at the problem that the molten iron in a foundry plant in China cooled too fast in the ladle, the heat storage of ladle lining was reduced by reducing the weight of the ladle lining materials, so as to slow down the temperature drop of molten iron. By measuring the temperature of molten iron at each time after the furnace, the influence of the light weight of the lining on the temperature drop of molten iron was studied. The results show that the temperature drop of molten iron decreases by about 40 ℃ when the weight of molten iron is reduced by 200 kg for 1 t molten iron ladle.