In this study, fly ash was modified by concentrated sulfuric acid, and it was used in the treatment of phosphorus-containing wastewater, then we have investigated the impact of the different modification conditions on the adsorption, the results show that: In the condition of 5g of fly ash by adding 0.15 mL of concentrated sulfuric acid and 3 mL water, 1.5 h of drying time, the temperature of 100°C, the effect of removaling Phosphorus is the best,and the adsorption efficiency can reach 94.6%. The adsorption rate was fast, and the adsorption can react in conditio...