In this study, the adsorption kinetics, isothermal adsorption model of orthophosphate (P) on soil from the Yeyahu Wetland of Beijing were investigated. The effects of pH and organic matter content on P adsorption were also analyzed. The results showed that the P adsorption equilibrium time was about five hours and Langmuir cross-shaped isothermal adsorption model well fitted the experiment data. pH had a significant influence on P adsorption. The P adsorption capability achieved the maximum value when the initial pH of the incubation solution was 8. Soil P adsorption capability increased with dissolved organic matters (DOM) increasing. When the concentration of DOM was 100 mg/L, the P adsorption capability reached the highest value and increased by 37.81%, 35.52% and 64.98%, respectively, for soil samples No. 3, 5 and 7 when compared with no DOM experiments. The results of XRD and FT-IR analysis of soil samples before and after P adsorption experiments reveal that kaolinite involved in P adsorption process and it is a key clay component for P adsorption on the Yeyahu Wetland soil of Beijing.