Abstract: Sustained-release dephosphorization tablet is a new type of aluminum salt inorganic compound flocculent, which can be slowly dissolved under the effect of scouring water while maintaining a certain intensity and shape. The characteristic and treatment effect of sustained-release dephosphorization tablets were studied through the application of sustained-release dephosphorization tablets to the wastewater treatment plant for the A/O process. Results show that the dosing equipment of sustained-release dephosphorization tablets is simple to use and easy to maintain. The tablets are suitable to phosphorus removal of small wastewater treatment plants. Under the condition of an average tablets dosage of 2 pieces per cubic meter in wastewater, the final effluent concentration of TP is 0.52-1.80 mg/L and the removal rate is 82%-87%.