In the present paper, Eu0.5Tb0.5(TTA)3Phen was synthesized and Eu0.5Tb0.5(TTA)3Phen/PMMA was prepared by in-situ polymerization. The structure of Eu0.5Tb0.5(TTA)3Phen/PMMA was characterized by FTIR spectra. Microscopic morphology and photoluminescence properties were investigated by SEM photographs and fluorescence spectra. The results indicated that polymer parts were attached with the rare-earth molecular parts in the composite luminescent materials.And Eu0.5Tb0.5(TTA)3Phen/PMMA could emit mostly characteristic fluorescence of europium ion and intense red fluorescence with a peak wavelength at 611.8 nm and a bandwidth of 10.4 nm(Purity: 0.990 5) under UV excitation at 365 nm. Its fluorescence intensity was found to be influenced with the content of MMA. It was demonstrated that Eu0.5Tb0.5(TTA)3Phen/PMMA was an excellent red photoluminescent rare-earth polymer material.