The invention discloses an internal discharge detection method of sulfur hexafluoride gas insulation equipment, comprising the following steps: A, providing a SF6 (sulfur hexafluoride) gas sample in the insulation equipment to be detected; B, after the sample is introduced in, detecting conventional ingredients in the gas sample by a TCD (thermal conductivity detector); C, After the TCD detects that SF6 almost flows out, inputting the sample into a FPD (flame photometry detector); D, detecting a trace product decomposed by SF6 via the FPD; and E, according to the content and the variation condition of the tract product, judging whether the SF6 gas insulation equipment has local discharge defects. In the invention, the internal insulation condition of electric equipment can be judged according to the chemical decomposer of SF6 gas. In the invention, a detection means for the internal insulation situation of GIS (Gas Insulated Switchgear) equipment is added, equipment station information is enriched, the internal discharge faults of GIS can be found as quickly as possible,equipment operation reliability is improved, a fault air chamber can be positioned quickly and accurately after discharge faults burst in GIS, and maintenance efficiency is improved.