Abstract: Aiming at a newly designed helix separator, the CFD numerical simulation technique was used to analyze the fluid flow velocity field and pressure loss distribution characteristics in the inlet pipe section, helical separation section and outlet pipe section of helix separator. In combination with PIV field test, the measurement and comparative analysis were performed on the fluid flow velocity field in the inlet and outlet pipe sections of separator. This paper also introduced the oil-water separation operating principle, structure parameter and PIV experimental procedure of helix separator. The results show that the newly designed helix separator has an obvious effect on helix diversion; it possesses the helical-flow separation flow field with long duration and strong centrifugal separation in the helical separation section and outlet pipe section. After the fluids flow through the helical separation section, a stable helical flow field can be formed in the outlet pipe section. Through the comparison of PIV test velocity measurement value and numerical simulation value between the inlet and outlet pipe sections of separator, it was found that they had a good consistence, thus verifying the reliability of simulation results. By analyzing the pressure loss of separator, the main pressure loss position of helix separator was determined. The results show that under the design working condition, the maximum pressure loss of separator is unable to exceed 90 kPa.