Numerical analysis was conducted to investigate the effect of wire length, spacing between wires, and wire bending angle, which are geometric parameters of a pipe-and-spike discharge electrode, on collection efficiency. Discharge electrode shape was optimized using the Near Orthogonal Array method. When the distance between collecting plates and the number of discharge electrode wires were fixed, a longer wire length and greater distance between the wires increased the collection efficiency, which was the highest when the bending angle of the wire was 160 degrees. Numerical results were validated through experiments. Collection efficiency of the electrostatic precipitator was increased by about 15% by the optimized discharge electrode, and power consumption and ozone generation showed little difference after optimization. Based on the results of this study, the optimization of the shape of various discharge electrodes is expected to effectively improve the collection efficiency of various types of electrostatic precipitators. (C) 2020 Elsevier B.V. All rights reserved.