In order to improve the separation efficiency of cyclone separator of oil and gas, the separator inlet shape (rectangle, round), inlet gas velocity, taper Angle of conical section, the diameter and the insertion depth of tracheal influence on separation performance were studied. The whirlwind oil and gas separator’s 3 d model were imported into the Fluent software of the ANSYS system to establish the simulation calculation model of oil and gas separator, the influence factors of affect the whirlwind separator separation characteristic of oil and gas were calculated and analyzed. The following conclusion: under the same conditions, as to the same size of particles, rectangular entry type separation efficiency is higher than round entry; The increase of the inlet gas velocity can improve the separation efficiency, but can lead the separator total pressure loss increasing, according to this model, as the inlet gas flow velocity was about 12.8 m/s, pressure loss was low, and the separation efficiency was higher; Separation efficiency increased slowly with conical section of the cone Angle , and the separation efficiency remained unchanged when the taper Angle was greater than 11.5 degrees; With the increasing of the pipe diameter, the separation efficiency was reduced, and the proportion of decreasing gradually increase; Separation efficiency increased and then decreased trend along with the change of the trachea insertion depth .