The pollutant emission of incinerator depends largely on the design of afterburner. As large amount of particulates are included in the flue gas from incinerator, the longer residence time is established by forming swirl flow in the afterburner. In this study, two afterburner configurations were selected. The 3-dimensional flow and combustion in the model are analyzed and emission characteristics were evaluated. Also, the flow in the model was visualized using water model. And the 3-dimensional flow was measured using the 5-hole pitot tube. The mixing characteristics of flow was investigated by measuring CO concentration distribution at the model exit. As a result, the effect of swirl flow on the mixing was relatively small and the effect of high velocity flow from nozzles was significant. (author). refs., figs., tabs.