In this paper, a dynamic arc model based on computation of coupled electric field and flow field for a high voltage (HV) SF6 interrupter has been investigated and analyzed. Moreover, for simulating the insulating performance and interrupting characteristics of the SF6 interrupter, dynamic variation of the arc in different interrupting cases, such as before current zero, approaching zero and after current zero have been established, and the compressibility and viscosity of SF6 gas in the whole interrupting course has been taken into consideration. Interrupting performance and dielectric recovery characteristic of the HV SF6 interrupter have been obtained and discussed. Fairly good representations of interrupting evolutionary processes within the arc-quenching chamber and arc dynamic characteristics have been achieved using the proposed model. And interrupting performance with higher precision has been obtained.