A novel fluorescent nanoparticle was prepared via a simple self-assembly technique based on water-soluble conjugated polymers (CPs) and Ag@SiO(2) core-shell nanoparticles. Core-shell nanoparticles with silver NPs core show a unique property referred to as metal-enhanced fluorescence (MEF). In the present work, the cationic conjugated polymer poly[9,9'-bis(6''-(N,N,N-trimethylammonium)-hexyl) fluorene-2,7-ylenevinylene-co-alt-1,4-phenylene dibromide] (PFV) was hybridized with Ag@SiO(2) NPs via simple self-assembly procedure, and given high stability, monodispersity. The fluorescence intensity of PFV after assembling on Ag@SiO(2) core-shell NPs is enhanced 1.3-fold compared with the fluorescence intensity of PFV assembled on silica NPs without silver cores for the MEF property of the Ag@SiO(2) nanostructure. Nanocomposite with bright fluorescence was obtained. Moreover, the nanocomposition exhibits good monodispersity and low cytotoxicity, which promote their application in cellular imaging. Furthermore, fluorescent nanoparticles with amendable peripheral surfaces can also be potentially obtained because of the easy modification property of CPs and give potential application in selective biological sensing and imaging.