The invention belongs to airplane power supply technologies and relates to an improvement on an airplane direct current power supply cable short-circuit protection circuit. The airplane direct current power supply cable short-circuit protection circuit is characterized in that a front-end current transformer and a rear-end current transformer are alternating current transformers; a signal processing circuit is composed of a rectifier bridge Z, a voltage following circuit (2) and a voltage comparison circuit (3). The alternating current transformers adopted for the airplane direct current power supply cable short-circuit protection circuit are simple in structure, do not need to be powered up by an external stabilized voltage supply, and are small in size, low in weight and low in cost; signals output by the alternating current transformers are alternating voltage signals, antijamming capability is high, mistaken protection is unlikely to occur, and reliability is high.