Abstract: High-voltage, large-capacity generator circuit breaker is a key power switchgear in power plants, and its rated current and fault current are beyond the capacity limit of a single vacuum interrupter, which needs to be connected in parallel with multiple vacuum interrupters. In order to deal with the dynamic current-sharing in the arcing process of vacuum multi-breakers in parallel, a vacuum arcing experimental platform was set up, high-current arcing experiments of 40 kA~80 kA were carried out, and the arc morphology was synchronously filmed by high-speed camera. According to the volt-ampere characteristics of vacuum arc with high current, the arcing process was divided into transient arc initiation stage, unstable arc evolution stage, and stable arc evolution stage. The influences of arc morphology and current level on volt-ampere characteristics were analyzed in detail. The circuit model of high-current vacuum arc based on volt-ampere characteristics at different arcing stages was proposed. The maximum simulation error of arc voltage was only 4.99% of the extreme value of arc voltage. Then, the simulation topology for parallel current-sharing of vacuum multi-breakers under high-current was established, and the influence of arcing delay and branch impedance on dynamic current sharing was studied. The absolute value of optimal arcing delay increased with the decrease of static current-sharing coefficient. Finally, the parallel current-sharing experiment of vacuum multi-breakers under 100 kA was carried out, a better current-sharing effect was achieved successfully, and the prediction ability of the proposed model was also verified. The conclusion of this paper will lay a foundation for improving the breaking performance of high-voltage and large-capacity GCB.