Abstract: Experimental researches were conducted for cleaning up contaminated soils with Polycyclic Aromalic Hydrocarbons(PAHs) by steam stripping technique. The cleaning apparatus system in laboratory was manufactured. Examinations on the influences of sludge mass, flow rate, concentration of sludge, temperature in high-pressure and low-pressure tube reactors on desorption efficiency were made. The experimental results indicate that the increasing mass flow rate decreases the desorption efficiency obviously and increasing reacting temperature raises the desorption efficiency. Normally, to obtain a high desorption efficiency, the mass flow rate of sludge should be less than 2 kg/s and the mean reacting temperature should be kept at 150～200℃.