Disclosed is a preparation method of water soluble antimicrobial polyacrylate silver salt. The water soluble antimicrobial polyacrylate silver salt is synthesized by dissolving a water soluble polyacrylate comprising sodium carboxylic group (—COONa) or potassium carboxylic group (—COOK) in water and then partially changing the sodium carboxylic group or potassium carboxylic group of the water soluble polyacrylate to silver carboxylic group (—COOAg) using silver salt in aqueous solution. Next, ultrafiltration membrane is used to remove the sodium salt or potassium salt generated from the metal ion exchanging procedure. The last step is to remove water from the ultrafiltration treated aqueous solution of polyacrylate silver salt to give water soluble antimicrobial polyacrylate silver salt.
