The green light fluorescent powder of Tb-sulfosalicylic acid-undecylenic acid used in white light emitting diode (WLED) is synthesized. Infrared (IR) spectra show that the ligands have coordinated with Tb(Ⅲ) ion successfully. Ultraviolet (UV)-vis adsorption spectra demonstate that the absorption of complexes mainly comes from the ligands absorption. Flurescence spectra suggest that the complex emits characteristic green light at 543 nm excited by 365 nm UV light. And this characteristic indicates that the complex can be used as photoluminescent phosphors of UV chips potentially. Thermogravimetric analysis manifests that the decomposition temperature of the complex is near 200 ℃, meeting the requirement of working temperature of WLED well. The fluorescence lifetime of the complex is 1.413 ms and the quantum yield reaches up to 42%. Furthermore, the singlet and triplet energy levels of the ligands are calculated by quantum chemistry, and the luminous mechanism of the complex is explored.