The invention discloses a method for utilizing waste heat of an aluminum electrolyzing cell. The method is characterized in that thermoelectric modules arranged on the outer wall of the aluminum electrolyzing cell can convert excessive heat energy generated by the aluminum electrolyzing cell into electric energy while keeping normal electrolyzing temperature in the aluminum electrolyzing cell; the thermoelectric modules acquires the heat energy by the outer wall of the aluminum electrolyzing cell; the low-temperature ends of the thermoelectric modules are cooled by wind or heat-conducting medium; the thermoelectric modules output the electric energy; and the aluminum electrolytic cell is provided with a plurality of the thermoelectric modules which are in series, parallel or series-parallel connection with each other. By adopting the method, the energy consumption in the aluminum electrolyzing process is reduced, and the energy utilization in aluminum electrolysis is improved by 0.5 to 5 percent; moreover, because a thermal balance control system of the aluminum electrolytic cell is added in the method, the original aluminum electrolytic process is not affected when the heat energy is utilized to generate the electric energy.