The invention belongs to sulfur recovery technology in the petrochemical and coal chemical industries and provides a burner of a tail gas burning furnace of a sulfur recovery device, which mainly comprises a burner body, a burning flame path, a gas gun (1), a primary air inlet (2) and an ignition gun (9), wherein the burning flame path and the gas gun (1) are positioned in the burner; primary airin a swirling flow enters the burning flame path to be mixed and burnt with gas sprayed out from the gas gun (1) and high-temperature smoke generated during burning is sprayed into a furnace hearth inform of high speed swirling flow; a tail gas inlet (4) is arranged on the burner, a tail gas path and the burning flame path are arranged independently, tail gases enter an interlayer of the body ofthe burner from the top part of the burner and are directly sprayed into the furnace hearth by a group of spraying pipes which are concentric with the burning flame path and are arranged around a lining of the burning flame path, and secondary air is sprayed out along the front end of an interlayer between the tail gas spraying pipes and an outer sleeve pipe to be immediately mixed and burnt withthe tail gases in the furnace hearth of the burning furnace; and at the same time, the secondary air is sprayed out in form of a swirling flow to be mixed and burnt with the tail gases.