Large amount of wastewater was generated during production process of coal chemical industry， in which the organic and ash content is high, color depth and refractory material is rich, and there is no cost-effective processing method. Biological treatment technology of wastewater treatment in coal chemical industry has become one of the most widely applied technologies because of its low processing cost. Hydrolytic acidification and biological contact oxidation process was used to treat coal chemical wastewater, the test results show that ：under optimal operation conditions, when the hydrolysis time of hydrolysis acidification and biological contact oxidation were 24 h and 14 h, removal rate of refractory organics in wastewater reached 5.04% and 41.6% respectively.