For energy-saving control of electrostatic precipitator with multiple electric-field stages, a new optimal control strategy to minimize the total power consumption by adjusting the secondary voltages subject to the dust outlet concentration requirement is suggested. The optimal problem is established on the basis of the proposed mathematical models on the secondary voltage relating to the outlet concentration, the secondary current, the primary voltage and the primary current, and is solved by the genetic algorithm. A practice application to an industrial precipitator is given as well. (C) 2013 Elsevier Ltd. All rights reserved.