Abstract: It is an important way to realize clean and efficient utilization of coal by the advanced coal chemical engineering,but coal chemical industry wastewater is difficult to be treated economically and effectively.That is mainly manifested in the high concentration of characteristic organic pollutants,such as heterocycles,aromatic hydrocarbons,long-chain alkanes,etc,which seriously restrict the sustainable development of coal chemical industry.The water quality characteristics of high concentration coal chemical wastewater and the step-by-step removal process of organic matter in wastewater were introduced,and the research status of coal chemical wastewater treatment was discussed.The characteristics and existing problems of each technology were analyzed.The selection of Dephenol extractant should be determined after technical and economic analysis according to the content of polyhydric phenol in waste water.At present,anaerobic + multi-stage aerobic process and the optimization and improvement process based on this process are the common processes for the treatment of high concentration organic wastewater in coal chemical industry,that mainly using the advantages of anaerobic process to improve the biodegradability of wastewater.Ozone catalytic oxidation technology based on no secondary pollution and no increase of salt content in waste water is a suitable choice for advanced treatment,but the effect of catalyst needs to be further improved.The biodegradation mechanism of typical organic pollutants such as phenols,benzene series,alkanes,polycyclic aromatic hydrocarbons and heterocyclic compounds in coal chemical wastewater was discussed emphatically.For example,phenol is first hydroxylated and transformed into catechol,and then metalytic and ortho cleavage can be carried out without bacteria.Resorcinol is first converted to pyrogallol and then further split in ring opening.The aerobic degradation pathway of benzene is relatively clear,however the anaerobic degradation pathway is not clear,but phenol and benzoic acid are important intermediate products in the anaerobic degradation process of benzene.There are four main oxidation ways of long-chain alkane biodegradation:single end oxidation,double end oxidation,secondary end oxidation and direct dehydrogenation.Firstly,different dihydrodiols are formed in PAHs degradation,which are further converted into catechol or gentianic acid for ring opening degradation.The biochemical degradation mechanism of nitrogen-containing heterocyclic pollutants is that denitrifying bacteria use organic matter as electron donor and oxygen in nitrate nitrogen as electron acceptor to carry out metabolic activities.At present,there are many researches on the degradation mechanism of characteristic organic pollutants and the analysis of degradation intermediates,and some achievements have been made.However,there are few researches on the toxicity of intermediates and the control of reaction in different degradation paths,which need to be further explored to find the most favorable reaction conditions and strengthen or accelerate the degradation of organic pollutants.The treatment of high concentration organic wastewater from coal chemical industry should strengthen the physicochemical pretreatment process,reduce the impact on water quality and quantity of biochemical system and make full use of anaerobic process to improve biodegradability,as well as reduce repeated pH regulation in the process of treatment,reduce the increase of salt in the system.It is also suggested to carry out the study on the analysis of the intermediate products,toxicity comparison and optimal control of different degradation paths of the characteristic refractory pollutants in coal chemical wastewater,which is the basis of strengthening the treatment of the coal chemical wastewater.