This invention is related to a method for producing polymer latex particle coated with silver nanoparticles. First, a polymer latex particle suspension is mixed with a silver nitrate solution in a weight ratio of 10:1 to 1:10 at 50° C. to 90° C. for 10 to 120 minutes to form a mixed solution. After the temperature of the mix solution is cooled to 50° C. to 85° C., a sodium citrate solution is added to react with the mixed solution for 10 to 240 minutes to form a polymer latex particle coated with silver nanoparticles, which has antibacterial activity.