With the proposal of carbon peak and carbon neutrality target, the tank multi-break vacuum circuit breakers with environment-friendly gas insulation is an effective methods to replace SF6 gas in the field of high voltage and ultra-high voltage. Firstly, the electric field simulation of tank multi-break vacuum circuit breakers is carried out. The scale test electrode is designed for the key position according to the electric field distribution, and the lightning breakdown test with different pressures, electrode distances and electrode structures are carried out. The results show that 0.9 MPa dry air and 0.9 MPa CO2 can satisfy the insulation configuration requirements of the tank multi-break vacuum circuit breaker. In addition, the surface flashover characteristics of the ceramic shell interface of vacuum interrupter are studied, the effects of gas pressure, metal particle attachment location on the surface flashover voltage of the ceramic shell are investigated, which provides guidance for the development of vacuum interrupters in ultra-high voltage field.