For multi-phase separation, developing high-performance cyclone separators is highly demanded. In this study, different divergent or convergent insertion pipes bFelow the vortex finder are employed to improve the separation performance. The impacts of insertion pipe geometrical configurations on the flow characteristics, pressure drop, and separation efficiency are systematically analyzed. The results reveal that the employed insertion pipe can significantly affect the static pressure distribution inside the cyclone. A longer insertion pipe length and larger tilt angle result in a wider central low-pressure area and smaller overall static pressure. The divergent insertion pipes increase pressure loss, while the convergent insertion pipes augment pressure loss. A larger insertion pipe length significantly impacts the axial velocity distribution. For divergent insertion pipes, the maximum central axial velocity increases with increasing tilt angles and then decreases. For small particles (d_p ≤ 5 μm), a convergent insertion pipe exhibits a better separation performance. When the particle diameter d_p ≥ 5 μm, divergent insertion pipes with larger angles and lengths can significantly decrease the pressure drop while guaranteeing satisfied collection efficiency. When L = 75 mm and θ = 60°, the pressure drop is reduced by 7.8%. This study may contribute to rationally designing high performance cyclone separators and also paves ways for improving the existing cyclone separators.