In blast furnace operation, the hot metal temperature is influenced by several operating factors, such as blast temperature, blast moisture and pulverized coal injection volume. In the case when an operating factor is changed intentionally in stepwise, one or more of the other operating factors are changed to compensate for the change so as to minimize the hot metal temperature deviation. Conventionally, in actual operation, the operating factors are changed in a trial-and-error fashion. This paper studies the operation planning method for a blast furnace which compensates for the hot metal temperature deviation accompanying a stepwise operation change with another stepwise operation change. First of all, a dynamic simulator for the blast furnace process is explained. Then the step responses of the hot metal temperature to several operation changes are analyzed. Next, switching operations of coke by PC operation and coke by blast temperature are planned. This is done using the simulated results to minimize the evaluation function which is defined as the integral of the square deviation of hot metal temperature. Satisfactory blast furnace operations are achieved based on this plan. Moreover, the unimodality of the evaluation function for such a switching operation of blast furnace is shown. The unimodal property means that the proposed operation planing method is applicable for construction of the furnace operation guidance system.