The invention provides a T-type electric transmission circuit fault indication system for detecting the fault of a T-type electric transmission circuit. The T-type electric transmission circuit with Qas a node is connected to three sides of M, N, and P; the M side of the T-type electric transmission circuit is provided with a switch KM, the N side of the T-type electric transmission circuit is provided with a switch KN, and the P side of the T-type electric transmission circuit is provided with a switch KP; a directional current transformer CM is arranged on the side of a Q line on a branch line PQ a directional current transformer CN is arranged on the side of a Q line on a branch line NQ, and a directional current transformer CP is arranged on the side of a Q line on a branch line CQ; each current transformer is connected with a fault indicator. A secondary value of each current transformer is obtained, and sudden change of current is used for starting; when the sudden change of current is larger than a set value, the logical value of the corresponding current transformer is set as 1, otherwise it is set as 0; in different power supply modes, when the T-type electric transmission line fails, it is identified that the fault is in the branch MQ, NQ or PQ or the node Q by a fault position logic identification table. The system can shorten the inspection time of power workers.