To improve the performance of garbage cleaning, a dust collector was designed based on the tornado principle and its structure parameters and extended domain were analyzed. The flow field of the dust collector was calculated using finite volume method, RNG k-ε model, and ANSYS FLUENT 16.0, and the influences of each structure parameter and extended domain parameters on the formation and dust suction effect of tornado were analyzed. The principle and the design scheme of the new type of dust collector were proposed. Results show that the upper part of the tornado was completely developed and the structure was stable, when the ratio of the height of the dust outlet to the diameter of the nozzle was 1.6. The tornado produced by the device had a distinct single vortex structure, and the wind speed near the surface of the nozzle was the largest and the dust suction effect was the best, when the ratio of the height between the nozzle inlet and the ground to the diameter of the cylinder was 0.2. When the inclination angle of diversion orifice was 45° or -45°, the structure of the tornado generated by the device was the most stable and the intensity was the largest. With the increase of the swirl ratio in a certain range, the intensity of the wind field structure in the proposed device was increased, which was beneficial to the improvement of dust collection efficiency. Moreover, the height and the diameter of the extended domain had threshold values, and when the extended domain parameter was greater than the corresponding threshold, its impact was negligible. By setting appropriate structure parameters, the proposed dust collector can form a tornado-like flow field with strong stability and good dust suction effect, and can achieve an efficient cleaning effect.