Red fluorescent agent Eu-xGd-(1-x)(BZA)-3Phen were synthesized by using low cost, good stability β-diketones ligands benzoylacetone (BZA) as the first ligand, and phenanthroline (Phen) as appropriate synergistic ligand, and doped inert rare earth ions gadolinium(Gd3+). The agent was characterized by elemental composition, IR, UV spectra, thermal properties, and fluorescence properties. The light-emitting mechanism of doped complex was studied. The inert rare earth ions co-fluorescence effect on Eu-xGd-(1-x)(BZA)-3Phen was explained by intermolecular energy transfer model. The results showed that this is an excellent performance and low cost europium complex.