The technical scheme of 252 kV、85 kA short-circuit current breaking device is proposed. The device has two parallel connected branches, each branch consists of a 252 kV、63 kA SF₆ breaker in series with a high coupled split reactor(HCSR). In order to study the current sharing and limiting characteristics of SF₆ high pressure arc under the action of HCSR, the magnetofluid dynamics arc model of the device is established through the coupled split reactor and external circuit. The current sharing condition, current limiting condition, arc characteristic and interrupting process of the device are simulated and analyzed. According to the actual interrupting condition and calculation results, the factors influencing the device’s current sharing and limiting characteristics are studied and the theory direction for its development and field application are provided.