Abstract: Corona discharge is one of typical partial discharge defects. Long-term corona discharge will cause insulation aging of electrical equipment,and even lead to breakdown of equipment under normal operating voltage. The strong electronegativity of SF₆ gas results in extremely weak spectral signals under low-voltage or high-pressure discharge conditions. Therefore,a method for enhancing the characteristic optical signal is proposed. In this method,according to the characteristic emission spectra of SF₆ under corona discharge,the narrow-band filter and a photomultiplier tube are used to enhance optical signal,so as to increase the signal-to-noise ratio（S/N）. First,a series of needle-plate corona discharge experiments with different electrode materials such as brass,stainless steel,and aluminum are carried out,and the characteristic spectral band and genesis of the excited radiation particla during the discharge process is analyzed,combined with the mechanism of SF₆ gas ionizing. Then,optical devices such as narrow-band filter,photomultiplier tube,and lenses are selected according to the characteristic spectral band,and an optical pulse signal detection platform is built,so as to enhance the characteristic optical signal. Finally,according to the characteristics of the optical signal during corona discharge,indicators and thresholds for identifying the discharge degree are proposed. Corona discharge experiments under high pressures verify the proposed indicators. A reference is provided in this paper for the detection and identification of partial discharge in SF₆ gas-insulated electrical equipment.