Each path in a multi-break parallel vacuum circuit breaker (VCB) is subjected to transverse magnetic field (TMF) from adjacent paths, leading to magnetic arc blow, which adversely affects the interruption capacity of the VCB. Therefore, it is necessary to design shielding structures to suppress the TMF from neighboring paths. First, a 1/6 equivalent finite element model of a multi-break parallel VCB is established, in which the arc is modeled using a magnetohydrodynamic (MHD) model. Second, based on the model, the TMF distribution inside the arc, the plasma density distribution, and the anode heat flux density distribution under different shielding covers are investigated and compared. To quantitatively evaluate arc characteristics, two indicators of arc are defined: BIAS_N and MAX_H. Compared with the traditional TMF indicator, these two indicators have a stronger correlation with the interruption capacity of the circuit breaker. The effects of shielding cover length ℎ and radius 𝑟 on these two indicators are studied. The optimal arc characteristics are observed when h = 300 mm and r = 110 mm. Finally, eddy current losses of shielding covers made of different materials are analyzed. With increasing electrical conductivity, eddy current loss first increases and then decreases, with a critical point at a conductivity of 1 × 107 S/m. Therefore, cast copper with high electrical conductivity is selected as the shielding cover material.