A swirl nozzle for exhaust aftertreatment comprises a nozzle body, a swirl flow core and an orifice plate. The swirl flow core comprises a swirl flow chamber in a rotary body shape and at least one runner tangent to the edge of the swirl flow chamber. The orifice plate comprises an orifice. The swirl flow core and the orifice plate are combined in the nozzle body to form the swirl flow chamber and the tangential runner. The swirl flow chamber is located in the nozzle body. The orifice is located in the center of the swirl flow chamber. The ratio SI of the total flow area of the tangential runner to the flow area of the orifice ranges from 0.75 to 1.5. When the SI is smaller than 1, the flow of the swirl nozzle is determined by the flow area of the tangential runner. Otherwise, when the SI is larger than 1, the flow of the swirl nozzle is determined by the flow area of the orifice.