The invention discloses a high-voltage side current quick-break protection method for an excitation transformer. A relay protection device samples high- and low-voltage side currents of the excitationtransformer and performs an effective value calculation. When a fundamental harmonic effective value of the high-voltage side current of the excitation transformer exceeds a fixed value Iset1, a fundamental effective value of the low-voltage side current of the excitation transformer is lower than a fixed value Iset2, and the excitation transformer does not have a magnetizing inrush current, it is determined that an internal short-circuit fault exists in the excitation transformer, thereby realizing the high-voltage side current quick-break protection of the excitation transformer. The high-voltage side current quick-break protection setting value of the invention does not need to be set according to the principle of avoiding strong excitation and avoiding a low-voltage side three-phase short-circuit condition, and only needs to be set according to the principle of avoiding a rated current condition, delay is avoided, and the problem that the conventional high-voltage side current quick-break protection methods of the excitation transformer are low in the sensitivity of detecting slight faults inside the excitation transformer.