The mechanical DC circuit breaker based on LC oscillating commutation can suppress the breaking arc, reliably remove the faulty line, and ensure the safe operation of the system. In order to analyze the influence of topological parameters of mechanical DC circuit breaker on its breaking, based on the principle of artificial zero-crossing arc suppression, a simulation model of DC circuit breaker is built in MATLAB/Simulink, and the effect of arc suppression under different models is analyzed. On this basis, the arc suppression simulation is carried out for the topology parameters of the circuit breaker under different commutation modes, and the influence of controllable parameters and uncontrollable parameters on the arcing duration is discussed. The simulation results show that in forced oscillation and self-excited oscillation commutation modes, controllable parameters have different effects on arcing duration, and uncontrollable parameters such as arc time constant and arc heat dissipation power have the same effect on arcing duration. This research results can provide effective reference for the design of arc suppression topology for DC circuit breakers.