Abstract: The cooling plate was used as the cooling apparatus in 3200 m³ of new No.1 blast furnace and the abnormal operation endangering the cooling plate life was discussed by numerical computations. A three-dimensional unsteady state temperature field mathematical model for the cooling plate and lining was established in the time of abnormal operation. As the slag-metal skull fell off, the gas flow rate and temperature abruptly increased, and peripheral gas overdeveloped, the temperature change of the cooling plate was computed. The influence of the thickness of the slag-metal skull and the cooling water rate on the temperature field of the cooling plate and the heat loss was analyzed.