A gas-liquid swirling-sparger (GLSS) configured along a toroidal distributor was developed based on swirling flow to enhance the efficiency of gas-liquid contacting. Gas-liquid contacting was visualized using a high-speed camera, the gas-liquid mass transfer coefficient was estimated through oxygen absorption experiments, and the hydrodynamic performance and bubble size distribution were analyzed. The results show that the continuous gas phase breaks into microbubbles under shearing action and pressure fluctuation caused by the three-dimensional strong turbulent flow in the GLSS; the bubble diameter distribution was unimodal with a median diameter (d(50)) of 625 mu m, and the oxygen absorption efficiency of the GLSS exceeded 70%. A general discrete model was developed for evaluating flow uniformity in parallel multiple GLSSs along a toroidal distributor. The experimental results were in good agreement with the theoretical calculations. The study is important for optimizing the use of gas-liquid contactors in engineering applications.