SF₆ gas mixture is one of the popular SF₆ alternatives. For the purpose of quantitatively evaluating the arc extinguishing performance of SF₆ mixtures,one-dimensional arc decaying model and Boltzmann equation are combined to divide the whole arc extinguishing process into thermal recovery stage,pre-dielectric recovery stage and post-dielectric recovery stage,which are evaluated by three parameters,namely thermal recovery rate,pre-dielectric recovery rate and post-dielectric recovery rate,respectively. The harmonic mean of the above three parameters is calculated as the harmonic average recovery rate to evaluate the arc extinguishing performance of SF₆-N₂,SF₆-CO₂,SF₆-CF₄ and SF₆-Air mixtures. Based on the proposed method,the effects of SF₆ proportion,buffer gas type and gas pressure on the interrupting performance of the SF₆ mixtures are preliminarily investigated. The results show that the overall arc quenching ability of the gas mixtures presents a decreasing trend as the lowering of SF₆ proportion. Among the four gas mixtures with SF₆ proportion ranging from 10% to 50%,the SF₆-N₂ gas mixture has the best interrupting performance,followed by SF₆-Air,SF₆-CO₂,and SF₆-CF₄ successively.