Abstract: In order to reveal the influence of the grid structure of low-voltage circuit breakers on arc extinguishing performance, a multi-field coupled arc simulation model of electromagnetic field, laminar flow field, and heat transfer field was established based on the theory of magnetohydrodynamics. The distribution characteristics of airflow, pressure, and temperature in the arc extinguishing chamber under the action of grids with different tilt angles and arrangements were analyzed. The influence of grid structure on arc extinguishing performance was discussed through taking arc voltage and arc ignition time as the characterization parameters. The results show that when the inclination angle of the grating θ is -10°, the obstruction effect of the grating on the airflow velocity is minimal and the arc extinguishing time is the shortest; Compared with the equal length arrangement, when using the staggered arrangement of grids, the arc voltage increases faster and the peak value is larger, and the arc ignition time is shortened by 0.4 ms.