Three rare earth(Sm 3+) binary chelates with Hexafluoroacetyl acetone(HFA), thenoyltrifluoroacetylacetone(HTTA)and dibenzoylmethide(DBM) as the ligands were synthesized, respectively. The absorption and fluorescence properties of the ligands and their chelates Sm(TTA)_3 , Sm (HFA)_3, Sm(DBM)_3 were investigated. For both Sm(HFA)_3 and Sm(TTA)_3, there existed a strong fluorescence peak in 645 nm, which ascribed to the transition of 4G_ 5/2→6H_ 9/2 of Sm 3+. However, the plentiful C-H grouped on the rare earth complex Sm(DBM)_3 presumably was quenched the luminescence by nonradiative dissipation of energy which brought from the high energy C-H vibrations, resulting in no peaks over all inspected wavelengths. It was also found the fluorescence intensity of complex Sm(TTA)_3 was the topmost, which was firstly attributed to two substituents on the ligand , -CF_3 and s. Secondly, among three complexes, the match of Sm 3+ and HTTA was the best and lead to stronger fluorescence intensity of complex Sm(TTA)_3, accord