Monodisperse,Eu (TTFA)₃-doped colloidal SiO₂ microspheres with different doping concentrations were synthesized by the modified St?ber method. The transmission electron microscope (TEM) and fluorescence spectrometer were employed to characterize the doping particles. It was found that the particles with the spherical morphology and the smooth surfaces had an average diameter of 300 nm and a size polydispersity of 3.5%. Visible luminescence of Eu³⁺ from Eu(TTFA)₃-doped colloidal SiO₂ microspheres was observed,with a lifetime of about 290 μs. Furthermore,the effect of doping concentrations (0.5～1.5wt. %) on the fluorescence intensity and the lifetimes was studied. The results showed that the fluorescence intensity increased with the doping concentrations,there was no obvious luminescence quenching during the processes of being excited,and the luminescence lifetimes were almost invariable while the doping concentrations were changed. Such fluorescence microspheres might have potential in active photonic crystals,microlasers and biological applications.