The utility model relates to a power system apparatus, particularly a non-contact local discharge on-line monitoring direction sensing apparatus for an electric generator, which is composed of two sets of signal couplers, signal transmitting units, filters and amplifiers with identical performances and a direction judging apparatus, wherein the signal couplers are connected with the filters and the amplifiers through the signal transmitting units, and the two amplifiers are respectively connected with the direction judging apparatus. The signal couplers comprise a parallel capacitor and a detecting resistor, the distance between pole plates of the parallel capacitor is 0.5 centimeters-1.5 centimeters, the sizes of the pole plates of the parallel capacitor are 25 centimeters * 15 centimeters, and the resistance value of the detecting resistor is 450 ohms-550 ohms; the length of the signal transmitting units is 1 meters-2 meters, and the input impedance is a cable of 50 ohms; the input impedance of the amplifiers is 50 ohms, and the gain of the amplifiers is 35 decibels-50 decibels. The utility model has the advantages of strong anti-electromagnetic interference performance, high sensitivity and convenient and safe use.