In　this　work,　core-shell　ZnSe/ZnS　quantum　dots　(QDs)　with　excellent　blue　light　emission　were　successfully　synthesized　in　aqueous　solution　using　thioglycolic　acid　as　a　stabilizer,　thiourea　as　a　sulphur　source,　and　zinc　acetate　dihydrate　as　a　Zn　source.　The　crystal　structure　and　optical　properties　of　the　as-synthesized　ZnSe/ZnS　QDs　were　characterized　using　X-ray　diffraction,　transmission　electron　microscopy,　X-ray　photoelectron　spectroscopy,　Fourier　transform　infrared　spectroscopy,　photoluminescence　(PL)　and　UV-Visible　spectroscopy.　The　ZnSe/ZnS　QDs　had　a　cubic　zinc　blende　crystalline　structure　with　an　average　particle　size　of　approximately　4.6　nm.　The　excitonic　emission　slightly　shifted　to　a　longer　wavelength　and　the　PL　intensity　increased　considerably　with　the　growth　of　the　ZnS　shells.　Meanwhile,　the　PL　quantum　yield　of　the　ZnSe/ZnS　QDs　increased　to　58.5%,　which　was　much　higher　than　that　of　ZnSe　QDs.　The　exciton　radiative　lifetimes　were　approximately　46.3　and　23.1　ns　for　the　core-shell　ZnSe/ZnS　QDs　and　ZnSe　QDs,　respectively.