Abstract [Objective] This study aimed to investigate the characteristics of phospho- rus adsorption on boiler slag and optimize the adsorption process. [Method] Boiler slag was used as an adsorbent in the single-grade adsorption process to dispose the rural domestic sewage. During the course, phosphorus adsorption kinetics and thermodynamics, adsorption operating curve and the minimum boiler slag dosage were analyzed and calculated. [Result] Langmuir adsorption isotherm could be ap- plied to describe the absorption of phosphorus with boiler slag, and the absorption kinetics was confirmed with the pseudo second-order equation. The maximum ab- sorption quantity and the initial absorption rate increased with the rise of tempera- ture, reaching up to 0.159 1 mg/g and 0.169 8 mg/（g.min） respectively at 40 ~C. Thermodynamic variables z~G~〈0 and AH~〉0 indicated that the entire process was a spontaneous endothermic reaction, and high temperature would facilitate the reaction of absorption. In the single grade adsorption, the minimum adsorbent dosage de- creased as the temperature rose; at 40 ~C the optimum mass ratio of boiler slag to wastewater was 3.31 kg/m3. [Conclusion] The adsorption process with boiler slag as adsorbent is an economical and effective approach for treating rural domestic sewage.