Wet electrostatic precipitation technology can effectively reduce the concentration of soot emission during thermal power generation. In order to study the effect of spray on the internal flow field of wet electrostatic precipitator during operation, the position of nozzle and the internal flow field of the wet electrostatic precipitator before and after using the nozzle were simulated by using the computational particle fluid dynamics (CPFD) method, the flow field, droplet distribution and spray trajectory were analyzed. The results show that when the nozzle is started, the velocity of flue gas near the nozzle is increased, and the velocity field of flue gas in the honeycomb tube is uneven. When the nozzle is arranged in the tube, it will accelerate the velocity of flue gas in the tube, which is not conducive to dust capture. The research results provide a theoretical reference for the adjustment of atomization region in practical engineering.