Abstract: The post-arc sheath development of vacuum circuit breaker(VCB),operating at a low current,was mathematically modeled and numerically simulated in article-in-cell Monte Carlo collision(PIC-MCC)method with VSim software.The influence of the plasma density,metal atom density and rising-rate of transient recovery voltage(TRV)on the sheath growth was investigated.The distributions of the potential,particle and particle density were calculated.The simulated results show that the ion and atom densities and TRV all have a major impact.To be specific,with all other parameters unchanged,an increase of the initial plasma density and/or atom density slows down the sheath growth;whereas an increase of TRV-slope speeds up the sheath development.