Abstract: Thermal value theory is mainly used to evaluate the effective utilization degree of energy, based on which the exergy value equations depending on the cold and the hot objects were derived by combining second law of thermodynamics. Taking the charging of hot steel blank and the preheating of air (coal gas) in heating furnace as examples, the thermal values and exergy values depending on temperatures of steel blank and furnace gas were calculated. The results showed that the thermal values and exergy values both increase with the hot charging temperature of steel blank and the preheating temperature of air (coal gas), and the exergy values depending on gas temperature even exceed its thermal values when heat transfer process is going on well and gas inlet temperature reaches or exceeds 1700 K, this means exergy gets better utilization than heat.