Abstract: CO₂ and its mixtures have already considered as potential substitutes for SF₆, so it is interesting to investigate their arcing characteristics used for new type circuit breakers. In this paper, an experimental device for simulating the arcing process of direct action type and puffer type high-voltage load switches was designed. An experimental platform for multi-parameter comprehensive measurement was built. The experimental research was carried out on the arcing characteristics of CO₂ and its mixtures with C4–PFN or C5–PFK, with stretching arc as well as nozzle-limited stretching arc under gas flow. The arc voltage, arc current, and current zero characteristics near the current zero were measured. Moreover, the Mayr arc model was applied to compare the post-arc breakdown characteristics of CO₂ and its mixed gas with C4–PFN or C5–PFK under different arcing modes. It is found that the air blowing effect has a strong promotion effect on the energy dissipation of arc during the small current period. In the arcing experiment, the thermal interruption capability of CO₂ gas is about 50% of SF₆. The thermal interruption capability of C5–PFK–CO₂ mixed gas is about 75% of SF₆, and the C4–PFN–CO₂ mixed gas has almost equal thermal interruption capability to SF₆. In the air-blowing arc experiment, the thermal interruption capability of CO₂, C5–PFK–CO₂ and C4–PFN–CO₂ mixed gas was about 45%, 68% and 91% of SF₆, respectively.