The process of adsorption-coagulation-advanced chemical oxidation is used to treat gentamicin wastew ater and the best conditions of coagulation and oxidation are selected. Under the condition of pH 8, the effect of the coagulating treatment of the waste water is better when PAC and CPAM are used as coagulants and their feeding amount are 400 mg/ L and 10 mg/ L, respect ively. Then, when pH is equal to 3, the wastewater treated above is oxidized by H₂O₂/ Fe²⁺/ UV. When the exposure time of UV-light is 6 h, the satisfactory treatment effect is obtained. Experimental results show that, for gentamicin wastewater, the removal ratio of COD_Cr is 99. 1% and decolourisation rate is 100% by using the process. The gentamicin wastewater treated can reach the effluent standard of medical waste water.