Based on a series of experiments, this paper studied the capacity of slag for removal of phosphorus from model wastewater.The results show that slag is effective in adsorbing phosphorus.The factors affecting the removal of phosphorus are the initial phosphorus concentration,pH value,adsorption equilibrium time and the amount of slag.When the concentration of phosphorus is 2~13mg/L,the amount of slag used is 5 g/L,the pH value is neutral, and the adsorption time is 2h,the removal rate of phosphorus can be higher than 99%.