Fluorescent probes based on quantum dots are emerging as ideal tools for sensing and imaging in biological applications owning to their great advantages such as high sensitivity and unique optical propeties.Effective optical imaging of tumor would allow early diagnosis, monitoring of disease progression and better therapy efficiency.To that aim, we prepared folate receptor-targeted and PEG-modified fluorescent probes based on silica-coated CdTe quantum dots.First, hydrophilic CdTe QDs stabilized with thioglycolic acid were directly synthesized in water phase.Then, highly fluorescent amino-functionalized core-shell CdTe@SiO2 particles were prepared via the water-in-oil (W/O) reverse microemulsion method.Finaly, through the use of amino groups, polyethylene glycol (PEG) and folate molecules were successfully bioconjugated with the CdTe@SiO2 particles.Furthermore, the as-performed nanoparticles were characterized by UV-vis absorption, fluorescence measurements, particle size, zeta potential and high-resolution transmission electron microscopy (HR-TEM).Besides, we demonstrated that encapsulating a silica film and PEGylation on CdTe QDs can noteworthly reduce the cytotoxicity of CdTe QDs via MTT assays.The bioimaging efficiency and specificity of the prepared fluorescent probes were investigated by KB cell labelling.In conclusion, folate receptor-targeted, PEG-modified and silica-coated CdTe quantum dots fluorescent probes are highly promising for a much wider range of biological applications such as tumor imaging.