The embodiment of the invention provides a coal gasification wastewater treatment method, and belongs to the field of the treatment of coal gasification wastewater, so as to improve the overall efficiency of the coal gasification treatment. The coal gasification wastewater treatment method comprises the following steps: adsorbing and filtering the gasification wastewater by virtue of pulverized coal to obtain a wastewater solution containing few impurities and pulverized coal adsorbed with many impurities; washing gasification coal cinders by virtue of the wastewater solution to obtain a wastewater solution containing an alkali metal catalyst; mixing, loading and drying the wastewater solution containing the alkali metal catalyst and the pulverized coal containing many impurities, and feeding a mixture into a gasification furnace to generate effective gas through reaction. The treatment method disclosed by the invention is applicable to the treatment of the coal gasification wastewater.