Abstract: In order to make activated alumina more widely used in the field of coal chemical wastewater defluoridation,and ensure that the fluoride of effluent could meet the requirements of class Ⅲ water body in GB 3838—2002 environmental quality standard for surface water( the fluoride in the effluent is reduced to ≤1 mg/L). The experimental effect of activated alumina on the fluoride removal performance of coal chemical wastewater was studied. The continuous defluorination experiment of activated alumina with particle size of 1-2 mm was carried out. The effects of the dosage,pH value of influent,residence time and adsorption time of activated alumina on the defluorination rate were studied to obtain the best experimental conditions for the fluorine content of coal chemical wastewater effluent to be less than or equal to 1 mg/L. The " practicality" of activated alumina was investigated under the best technological conditions. Finally,the reaction kinetics of activated alumina for removing fluorine was studied. The experimental results show that the larger the activated alumina loading is,the greater the fluoride removal rate is,and the lower the fluoride content in the effluent is. When the loading amount of activated alumina is ≥60 g,the fluoride content in the effluent can still be maintained at ≤1 mg/L after 40 h of continuous adsorption; The smaller pH is,the greater the fluoride removal rate is. When the pH is ≤6,the fluoride content in the effluent can still be maintained at ≤1 mg/L after 40 h of continuous adsorption; The longer the adsorption time is,the lower the fluoride removal rate is. When the adsorption time is ≤45 h,the effluent fluoride content is less than or equal to 1 mg/L and when the adsorption time is more than 45 h,the content of fluoride in the effluent is more than 1 mg/L; The longer the residence time is,the higher the fluoride removal rate is. When the residence time is 6-8 min,the effluent will be continuously adsorbed after 40 h,and the fluoride content is ≤1 mg/L. When the activated alumina loading is 60 g,the influent pH is ≤6,the residence time is 6-8 min,and the adsorption time is ≤45 h,the fluorine content of the outlet water can be kept at≤1 mg/L. The activated alumina after defluorination is regenerated with aluminum sulfate and the experiment is repeated,the effluent fluorine content is still well maintained below 1 mg/L,indicating active oxidation aluminum has a good " practical application" for removing fluoride from coal chemical wastewater. At the same time,the reaction kinetic equation of activated alumina to remove fluoride is a first-order reaction,and the adsorption effect is best when the fluorine content is 3 mg/L.