Glowing contact in low voltage electric circuit is mostly caused by poor electrical contact, which is easy to cause fire. The existing electrical detection method is based on the voltage of glowing contact, while the location of glowing contact is often unknown, causing detection difficulties. An experimental platform for glowing contact is built, and the reasons of high-frequency component are explained. A time-frequency domain detection method for glowing contact based on the current of the parallel filter capacitor on the load side is proposed. The high-frequency components generated by glowing contact in the capacitive current are detected. The characteristic frequency bands of glowing contact are analyzed to be 5–15 kHz and 20 kHz ~ 30 kHz. The electrical signal characteristics of glowing contact under different wire cross-sectional areas, wire materials and loop current amplitudes are studied. The amplitude of high-frequency component is proportional to the cross-sectional areas of the wire, which is conducive to the detection of glowing contact. The temperature of glowing contact is proportional to loop current amplitude, which gradually approaches the boiling point of cuprous oxide. The high-frequency component generated by brass wires are richer than those generated by copper wires, but the power spectrum of the characteristic frequency band decreases, which are not conducive to the detection of glowing contact.