The utility model discloses a gaseous tail gas absorbing device of sulfur hexafluoride, which comprises a housin, relative air inlet and the gas outlet of being equipped with on the outer wall of casing, be equipped with first absorption unit, second absorption unit and the third absorption unit connected in order in the casing, air inlet and the first entry linkage that adsorbs the unit, the exit linkage of gas outlet and third absorption unit. The utility model is simple in operation, use reliably, can guarantee witnessed inspections and staff's personal safety with detecting the toxic gas complete absorption in the waste gas, solved and caused the problem of injury at on -the -spot sulfur hexafluoride decomposition product gas to the human body, improved work efficiency.