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CdSe∶Sm nanocrystals (NCs) were synthesized by a water phase method,and their structures,shapes and optical properties were further characterized.X-ray diffraction (XRD) analysis suggested that both the CdSe and CdSe∶Sm NCs contained (111),(220) and (311) lattice planes in the zinc blende structure overlapped with the (002),(110) and (112) lattice planes in the wurtzite structure,and the diameters were about 4.2,3.3 and 2.3 nm for CdSe,CdSe∶Sm(8％) and CdSe∶Sm(10％) NCs,respectively.All of the CdSe∶Sm NCs were monodispersed and uniform spherical nanocrystals.The CdSe∶Sm(10％) NCs prepared with different reaction times exhibited constant absorption spectra at 430 nm and a fixed emission peak at 581 nm.Compared with those of pure CdSe NCs,the fluorescence emission of CdSe∶Sm(10％) NCs blueshifted 20-36 nm,and the absorption peak initially redshifted and then blueshifted with the prolongation of reaction time.In addition,the Sm2+ doping decreased the fluorescence lifetime and increased the quantum yields (QYs) of CdSe NCs.The QYs of CdSe∶Sm NCs increased initially and then decreased with the increase in the amount of doped Sm2+.The initial pH and charge compensator concentration also exhibited significantly enhanced fluorescence emission of CdSe∶Sm NCs.