The invention discloses a three-layer secondary air low nitrogen oxide (NOx) swirling burner which comprises a central air pipe as well as a primary air pipe, an inner secondary air pipe, a middle secondary air pipe and an outer secondary air pipe which are concentrically arranged at the periphery of the central air pipe from inside to outside, wherein the air inlets of the inner secondary air pipe, the middle secondary air pipe and the outer secondary air pipe are provided with swirling adjusting mechanisms for generating straightly-flowing secondary air or secondary air with variable swirling intensity by virtue of the respective secondary air pipes; three independent air boxes are sleeved outside each secondary air pipe; and the air volume of each secondary air pipe can be adjusted by air box baffle plate adjusting mechanisms on the air boxes. By adopting the structure of the low NOx swirling burner, the partial grading burning effect of the burner is enhanced and the high temperature smoke reflow is increased, thus finally achieving the aim that the burner burns coals stably and reduces the NOx generated by burning. The three-layer secondary air low NOx swirling burner has a simple structure, is easy to manufacture and install, is high in industrial applicability, is applicable to various coals and guarantees the burning stability and the burning economy of a boiler.