Achieving homogenized temperature distribution in continuous casting billets is critical in the application of direct rolling. A method that reduced the temperature differences in a continuous casting billet using an electric current was proposed. Numerical simulations revealed that the Joule heat generated by an alternating current with high frequency could supply an external heating effect and improve the temperature distribution in the continuous casting billet. Results showed that this heating effect increased with an increase in the current frequency and decreased with an increase in the moving speed of the billet. In addition, it was shown that the Joule heat generated by the current could reduce the temperature gradient in both the radial and longitudinal directions of the continuous casting billet. A theoretical model was established to calculate the heating power required to generate homogenized temperature distribution in a continuous casting billet. This study provides a theoretical basis for optimizing current parameters in numerical simulations.