For realizing the straight bar rolling, one method will be used in a bar line that uses the mode of induction heating to replace the mode of conventional gas heating.For induction heating, there are two points need to be considered, one is the temperature of the slab entering the induction heating furnace, the other is whether the temperature of the casting billet can reach the goal after induction heating.This paper is to solve the second problem.Slab size is 150 mm square, 12 m in length.The temperature of the exit of the furnace should be equal to or greater than 960 ℃, and that of the entrance should be reach 810℃~ 860℃.In this paper, according to the design requirements, the slab temperature field during induction heating is analyzed by using finite element simulation, and it is to provide technical support for the determination of process parameters and type selection of equipment.