The invention discloses a method for using a negative sequence component for achieving T wiring line fault branch circuit selection. The method includes the steps that fault phase negative sequence voltages and fault phase negative sequence currents at protective installation positions of three branch circuits of a T wiring line are respectively measured; the fault phase negative sequence voltages, at the T junction point, of the three branch circuits are respectively calculated, the fault phase negative sequence voltage, at the at the T junction point, of the third branch circuit is subtracted by the average of the sum of the fault phase negative sequence voltages, at the T junction point, of the other two branch circuits to obtain a voltage difference value; whether the angle, ahead of the fault phase negative sequence current, at the T junction point, of the third branch circuit, of the voltage difference value is smaller than zero or not is judged, and if yes, the third branch circuit is judged to be a fault branch circuit of the T wiring line. The method is suitable for unsymmetrical fault types of the T wiring line fault and fault branch circuit selection in the whole fault process after the T wiring line fails, a selection result is not affected by transition resistance, a load current and fault positions, and the fault branch circuit of the T wiring circuit can be judged accurately.