In this article we studied the effect of surface modification of polyester (PET) and silk fabrics by their exposure to cold plasma. The cold plasma was carried out using oxygen as a working gas and different plasma device parameters have been studied such as: different time, different current and different hydrostatic pressure using plasma/Oxygen. Treated fabrics are characterized by the measurements and evaluation of mechanical properties, air permeability, Electron Spin Resonance (ESR) and the changes in surface morphological of pretreated fabrics were characterized by Scanning Electron Microscope (SEM) and Energy Dispersive X- Ray Analysis (EDX)). The nano-silver particles were prepared by green synthesis method, then were characterized by Transmission Electron Microscopy (TEM) and Zeta Potential and particle size. The exposed plasma fabrics at optimum conditions were modified with the prepared nano-silver. The antibacterial activity properties for treated fabrics against gram positive bacteria (Staphylococcus aurous) and gram negative bacteria (Escherichia coli) were examined. The SEM results confirmed that there was a significant increase in roughness of the surface for all treated fabrics . The results of mechanical properties showed that plasma treatment had not destructive effect on the physical properties of the fabrics. The results obtained clarify that the ultraviolet protection factor (UPF) values increase for polyester exposed fabrics but the increase is not significant for silk fabrics while antibacterial properties were highly improved by all treated fabrics.