An experimental investigation has been made of the cyclone dust collector with a perforated internal rotating cylinder. The size of the rotating cylinder is of 0.5D, where D is the diameter of the cyclone body, and is the same size as the outlet tube. The dust collection efficiency as well as the pressure loss has been measured when the inlet flow speed is 9 ~ 21 m/s and the rotating speed of the cylinder is 37 ~ 63 m/s. The velocity and pressure distributions were also measured. It is found that the collection efficiency decreases and the pressure loss increases as the rotating speed increases. It is also shown that both the inward radial velocity and the upward vertical velocity become large as the rotating cylinder increases its speed. As a whole, the rotation of the internal cylinder makes worse performance of the cyclone dust collector.