The separation performance of self-made inline deliquidiser apparatus was studied with air-pure water mixture as experimental medium and using weighing and variable controlling methods, and the effects of inlet velocity and liquid content on the separation efficiency and pressure drop of the deliquidiser apparatus were examined. The results show that when the inlet velocity is kept constant, the separation efficiency increases with increasing of the liquid content, then it will decline while the liquid content exceeds a certain value which increases with increasing of the inlet velocity, and the effect of liquid content on the pressure drop is not significant. The separation efficiency and pressure drop increase with increasing of the inlet velocity, in the range of the experimental droplet particle sizes (50~80 mm), when the inlet velocity increases from 14 to 22 m/s, the separation efficiency increases from 39.17% to 77.85%, and the pressure drop from 2200 to 3400 Pa. The experimental results show that the designed inline deliquidiser has good separation effect. Key words: inline deliquidiser; gas-liquid separation; separation efficiency; inlet velocity; pressure drop