In this study, the distributive mixing performance of Dulmage screw, which was one of the fin type screw for a single-screw extruder, was evaluated experimentally and numerically. In the experiment, the performance was evaluated by measuring the uniformities of red color on the cross-sections of the extrudates which consisted of low density polyethylene and red color pigment. The performance was basically in proportional to the screw rotation speed, but the performance decreased at the certain screw rotation speeds. In order to investigate the reason why the performance had decreased, the finite volume method with the particle tracking technique was conducted. It is known that the performance increases with an increase of the weighted average total strain (WATS) which were added to particles in the screw. However, the WATS was in proportional to the screw rotation speed, and the fluctuation of the WATS didn’t corresponded to that of the performance. On the other hands, the independent component of the WATS on the screw rotation speed, which were obtained by detrending the relationship between the screw rotation speed and the WATS, changed non-monotonically and vibrationally, and the fluctuation of the component corresponded to that of the performance. Under the condition that the performance had decreased, most of particles circulated between the screw surface and the barrel surface in fin section, and were distributed near the screw root at the outlet of fin section again. And, these particles moved on the screw root as the cluster in the following torpedo section. Due to the movement, the performance had decreased because the strain rate which were added to particles became lower in the screw. From these results, it became clear that the component might be available as the parameter to judge whether the flow patterns which prevented the WATS from increasing occurred in the screw.