To clarify the dependence of arc duration on atmosphere, experiments were conducted under conditions of air, N$_{2}$, Ar, He and CO$_{2}$ with the pressure of 0.1,MPa in a 14,V/28,V/42,V circuit respectively. A quantitative relationship between arc duration and gas parameters such as ionization potential, thermal conductivity was obtained from the experimental data. Besides, the inherent mechanism of influence of atmosphere on arc duration was discussed.