The detection analysis of ultra-high voltage sulfuryl fluoride（SO

2

F

2

）gas

as the characteristic component of decomposition product of sulfur hexafluoride（SF

6

）in the gas compartment of gas insulated switch-gear（GIS）

can realize the early latent fault identification of GIS equipment.A Fourier transform infrared absorption spectrometer（FTIR）system with adjustable optical path cell temperature and intensity of pressure is set up.The infrared absorption spectrum of SO

2

F

2

gas and its cross-interference characteristics are analyzed by using the absorption spectrum parameters obtained from FTIR experiment and HITRAN database.The center wavelength of 2 763 cm

-1

is picked as the characteristic absorption peak of SO

2

F

2

gas and the infrared absorption characteristics of SO

2

F

2

affected by temperature and pressure near this band are studied.The results show that the infrared spectra simulated by HITRAN database is in good agreement with the experimental data.When the intensity of pressure changes in the range of 50～300 k Pa

the peak absorption coefficient of SO

2

F

2

gas in the wave number range of 2 710～2 810 cm

-1

increases with the increase of intensity of pressure

and the change rate of absorption coefficient at 2 763 cm

-1

with the intensity of pressure is 0.002 4 cm

-1

/k Pa.Increasing the intensity of pressure can improve the gas detection sensitivity.When the temperature changes in the range of 298～338 K

the peak absorption coefficient of SO

2

F

2

gas in the wave number range of 2 710～2 810 cm

-1

decreases with the increase of temperature

and the change rate of absorption coefficient at 2 763 cm

-1

with intensity of pressure is 0.002 cm

-1

/K.The analysis results are of great significance for research of infrared optical detection technology of SF

6

decomposition product SO

2

F

2

of GIS equipment fault.