Whether the cyclone separators have a high-efficient body shape is a problem that has been ignored for a long time. A series of cyclones with elliptical bodies were designed and manufactured by SLA 3D-printing. The separation performance and flow field of the cyclones were investigated using the experimental and CFD methods, respectively. The detailed flow features, such as streamlines, pressure and velocity profile distribution, and special flow phenomena of the circumferential acceleration/deceleration of the swirling gas, are analyzed. The experimental results reveal that the elliptical cyclones with a/b = 1.2 and 0.83 have about 2% increment of separation efficiency and 43% reduction of pressure drop, as well as satisfactory robustness to the particle properties and operating conditions. The circumferential acceleration/deceleration of the swirling gas creates an additional inertial force for the particles, thereby improving the elliptical cyclones' performance. The results provide innovation ideas for designing and manufacturing the better-performance cyclones.