The invention relates to the technical field of electric power equipment, and discloses a voltage transformer primary-side high-voltage fuse fusing judging device and a judging method thereof. As forthe voltage transformer primary-side high-voltage fuse fusing judging device, a resonance elimination branch is in parallel connection with the opening triangular output end of a three-phase voltage transformer, the resonance elimination branch comprises a resonance elimination resistor, a wire break judgment resistor input circuit, and a current detection module, and the resonance elimination resistor, the wire break judgment resistor input circuit, and the current detection module are in series connection in order; and the current detection module and the secondary-side three-phase output end of the three-phase voltage transformer are both connected with a control unit. According to the voltage transformer primary-side high-voltage fuse fusing judging device and the judging method thereof, existing resonance avoidance devices are modified, the wire break judgment resistor input circuit and the current detection module are additionally arranged, thus the fusing judging device can increase the resistance of the resonance elimination branch when the opening triangular current breaks suddenly, whether a primary-side high-voltage fuse of one of the phases of the three-phase voltage transformer is fused or not is judged through the decreasing condition of the amplitude of the voltage of one of the phases, thus normal operation of a power grid system is further ensured, and inspectors are prevented from being hurt when the fusing accident is not found in time.