The adsorption and de-sorption properties of polycyclic aromatic hydrocarbons (PAH) which was represented by pure phenanthrene, on activated carbon were investigated. The influences of solvent (acetone,carbon tetrachloride, tetrahydrofuran, ethanol or distilled water), time and manner (with ultrasonic or not) on the desorption efficiency were investigated. The results show that the de-sorption efficiency reaches 91.40% which exhibits the highest efficiency when the ethanol is used as the de-sorption solvent and the system was treated with ultrasonic technology. The desorption test was also carried on the raw coconut shell-based activated carbon and it was not being used before. This determination is to understand the “baseline background” and the purity of raw activated carbon characteristics. The content of total de-sorption amounts was 0.043% of raw activated carbon. Through GC/MS analysis,the main desorption substance defined was 10-undecenoic acid methyl ester.