The invention relates to a coal chemical wastewater treatment method, in particular to a chemical wastewater treatment method. The invention aims to solve the problems of the chemical wastewater treatment method such as bad outlet water quality and high operational cost. The method comprises the following steps: pretreating coal chemical wastewater to be treated; then carrying out hydrolytic acidification treatment, external circulating anaerobic treatment, anaerobic sedimentation treatment, adjusting hydrolytic acidification treatment, contact oxidation treatment, sedimentation treatment, A / O treatment, sedimentation treatment, deamination treatment, coagulating sedimentation treatment and aeration biological filter tank treatment, wherein the temperature in an external circulating anaerobic tank is controlled within the scope of 32 to 35 DEG C; the hydraulic detention time is 24 to 36 h; the sludge concentration is controlled between 50 and 100 g / L; the volume load is 5 to 10 kg COD / m.d ; and the pH value is controlled between 7.0 and 7.5. The invention has the advantages of flexible operation, impact load resistance, low operating cost and good treatment effect; after the coal chemical wastewater is treated by the treatment method, the outlet water quality completely can achieve the wastewater comprehensive discharge standard regulated by the State.