Using starch as the stabilizing agent, glucose as reducing agent, nano-size silver particles colloidal sols have been synthesized via ultrasonic irritation in aqueous solution. The nanoparticles size distribution in typical colloidal sol is from 15 to 45 nm. The silver nanoparticles-PE blend film with silver content of 86 ppm was prepared by mixing silver nanoparticles colloids sol with the PE master batch and then by film blowing. The silver nanoparticles-PE blend film and the prepared nano-silver sol show effective antibacteial activity to the Staphylococcus aureus and Escherichia coli. The pear fruit package application of the silver nanoparticles-PE blend film has demonstrated that the film has effective fresh preservation ability for the packaged fruits and vegetables.