The invention discloses a cascaded multi-level tundish electromagnetic heating power supply comprehensive control method. A cascaded multi-level tundish electromagnetic heating power supply is a cascaded full bridge multi-level modularized structure for which the comprehensive control method comprises the following steps: voltage, an input current and a ring current of a three phase power grid are respectively converted to be in a two-phase stationary coordinate system and a three-phase stationary coordinate system; the input current and the ring current are controlled in a dead beat manner, and a balance control strategy is adopted for capacitor voltage in a bridge arm; a quadratic sum and a quadratic difference of upper and lower bridge arm module capacitor voltage in a horizontal direction and a voltage error square of the upper and lower bridge arm module capacitor voltage in a vertical direction are used as voltage control quantity; unbalanced power in a three phase alpha beta 0 stationary coordinate system can be obtained via the voltage control quantity; thus module voltage balance is achieved via control over bridge arm energy. Via use of the cascaded multi-level tundish electromagnetic heating power supply comprehensive control method, rapid tracking control of input and output currents can be realized, control efficiency is improved, and requirements for induction heating power supply energy balance and heavy current rapid transformation are satisfied.