ABSTRACT In this work, the effect of electrodynamic flow (EHD) on particle motion behavior is studied numerically on the basis of the single needle–plate electrode configuration. The interaction between primary–secondary flow and the trajectory of particles in a 3D environment is presented. In addition, the effects of the needle-shaped discharge electrode structure on the electric field and the flow field distribution are explored. Results show that the sharp surface of the needle tip causes high-intensity discharge that creates high-speed ion wind near this tip. The maximum velocity of the ionic wind can reach 9.028 m/s at applied voltage and inlet velocity of −60 kV and 1 m/s, respectively. This high-speed ion wind generated near the needle tip can increase the migration speed of particle. Moreover, the phenomenon that 90% of 1 µm particles penetrate the outlet surface indicates that the EHD flow negatively affects the capture of fine particles. The relationship among the injection position, residence time, and escape velocity of the particles further confirms that secondary flow seriously affects fine-particle capture. These results can help improve and optimize an electrode structure that reasonably uses high-speed ion wind to capture particles and prevent fine particles from escaping.