The effect of biology activity on liquid indicators (pH, SCOD, VSS ,SOP etc.) and solid indicators (PHA , hepatin, TP etc.) of phosphorus-rich waste sludge during the anaerobic digestion were studied in this paper. Sludge used in this study was obtained from a sewage treatment plant in which the A/O process was used. The results indicated that the hydrolyzing of waste sludge was promoted by the addition of bacterium inhibitor in the beginning of experiment. However, the presence of bacterium inhibitor was disadvantage to both hydrolyzed and biological release mechanism of phosphorus in anaerobic digestion system.