Abstract: Sulfonated coal possesses very good adsorption action for phenols and its homologues. The experiment mentioned here systematically investigated the adsorption rates, the equillibrium concentrations and the factors affecting the adsorption action of the sulfonated coal for phenolic compounds. The results obtained show that the adsorption rates of sulfonated coal for phenolic compounds are very rapid and the equillibrium reached after 90 minutes. Among the homologues, the adsorption of phenol is preferential. The experiment proves that the adsorption is substantially the action of the active center of sulfonated coal upon the hydroxyl group on the aromatic rings. Applying the above conclusions, the approximate total quantity of phenolic compounds adsorbed on sulfonated coal may be obtained when various samples of waste water of different phenolic compound content are treated with sulfonated coal. In case the operation temperature is raised to 70℃, the adsorption concentration decreases apparently, but low temperature (<10℃)is also disadvantageous. Generally, temperature in the range 20-30℃ is favorable. It is obvious that high temperature favors the desorption of phenolic compounds from sulfonated coal. When the pH value of the solution gets above 8, the adsorption of phenolic compounds on sulfonated coal decreases apparently, a sharp drop being observed. The presence of sulfides in solution weakens the adsorption of phenolic compounds on sulfonated coal on account of the formation of phenolates. Other impurities such as amino- and cyano- compounds as well as organic acids do not show apparent influence, if their concentration is not higher then their usual content in waste water. Excessive alkali in solution apparently suppresses the adsorption ability of sulfonated coal for phenolic compounds, and even blocks up the action entirely. In short, either in view of the adsorption rate or the factors affecting the adsorption process, the facts obtained prove that the dephenoling action of sulfonated coal is an adsorption rather than an ion-exchange process.