Based on the analysis of adsorptive features of oyster shells, the researches on the treatment of phosphorous wastewater with oyster shells and the effect of temperature on phosphorus removal were carried out. XRD was used to characterize the crystalline phases, and the main component of oyster shells was shown to be CaCO3. When the pretreatment temperature reached 800 ℃, some CaCO3 decomposed into CaO. As the temperature was further raised, CaO increased gradually. Via SEM testing, the oyster shell was a kind of natural porous materials. The pore wall partially collapsed from 550 to 900 ℃. No obvious porous structure was found at 900 ℃. However, without preheating, the oyster shell phosphorous removal material can not adsorb the phosphorus. Pretreatment made calcium activate, thus greatly increasing the absorption of phosphorus.