The invention discloses a fault diagnosis method of sulfur hexafluoride electrical equipment. The method comprises the steps that the content of foreign gas in the electrical equipment is firstly obtained, and whether the equipment is in a noticed state or an abnormal state is judged through the content of HF in the gas and the content of fluorinion in the gas; meanwhile, whether high-temperature overheating faults exist in the equipment or not is judged through the content of sulfur dioxide. Whether the electrical equipment is normal or abnormal or out of order is judged by measuring the content of the HF, the content of the SO2, the content of SOF2, the content of SO2F2, the content of CO and the content of CO2 in the foreign gas in the sulfur hexafluoride electrical equipment. The fault types of arc discharging, low-energy discharging and high-temperature overheating occurring in the equipment can be judged according to whether increase tendency exits in the content of the CO and the content of the CO2 or not through the parameters of the content of the SO2 and the ratio of SOF2/SO2F2, bases can be provided for safe and reliable running of the sulfur hexafluoride electrical equipment, and effective reference can be provided for operation and maintenance personnel for equipment maintenance.