The adsorption characteristic to the phosphorus in polluted water was discussed between two different calcium content fly ash biological filtering materials. The result showed that the under a certain temperature, the adsorption characteristic correspond with Langmuir equation. The maximum phosphorus adsorption capacity reach 93.7％and 63.5％; When the temperature was higher and contact time was longer, the adsorption capacity was more, but in 3 hours, the adsorption equilibrium was both got. The phosphorus adsorption capacity related with the calcium content and the surface adsorption power result by vast pore in material interior has strengthened the adsorption action. Level-one variable dynamics model could be used to describe the absorb process.