In order to evaluate the gas-liquid separation performance of cyclone separator for purification of natural gas at low liquid concentration，membrane filtration method and optical particle counter Welas 2000 were applied to measure the overall collections and droplet size distributions，respectively，with inlet velocities of 8—24 m·s-1 and liquid concentrations of 0.1—2 g·m-3 and under atmospheric pressure and room temperature.Comparisons of separation performance have been done between gas-liquid and gas-solid separation under the same inlet velocity and liquid/solid concentration.The results of experiments showed that the gas-liquid separation efficiencies increased with the increase of inlet velocity of 8—24 m·s-1 and liquid concentration 0.1—2 g·m-3.The separation efficiencies of gas-liquid separation were 2%—6% higher than those of gas-solid separation under the same conditions.The droplets with the diameter size bigger than 4 μm could be removed clearly，however，there were particles with the diameter bigger than 10 μm existed in cyclone separator outlet.