Abstract: The way to remove Ag⁺ from wastewater using chitosan as flocculant was investigated including the effects of pH value, ion concentration of Ag⁺, flocculant dose and flocculating time on removal rate. Experimental results indicated that the suitable pH value varies from 7 to 8 with which the removal rate of Ag⁺ is 100% if the mass concentration of Ag⁺ is less than 20 mg/L in water. And the removal rate will be over 99.9% even if the mass concentration of Ag⁺ is very high. The optimal flocculating time is 4h by which the removal rate of Ag⁺ will still be 99.98%; Overmuch or insufficient dose of chitosan will affect the removal of Ag. The flocculation mechanism of using chitosan to remove Ag⁺ was further analyzed.