Luminescence enhancement effect of Tb(TTA)(3)Phen (TTA = 2-thenoyltrifluoroacetone; Phen = 1,10-phenanthroline) on Eu(III) in Langmuir-Blodgett (LB) films was studied in this paper. Luminescent films with strong intensity were assembled by mixing Eu(TTA),Phen with different molar percentages of Tb(TTA)(3)Phen with the help of arachidic acid (AA) (AA/complexes = 1:1. in molar ratio). Meanwhile. the film-forming behaviors of monolayers were observed on a corresponding composite subphase saturated with film-forming material(s), TTA and Phen. The monolayers and LB films were characterized by UV-Vis spectra and fluorescence microscope photographs. The results show that they are homogenous and can be transferred onto the substrates successfully. Finally the mechanism of luminescence enhancement effect of Tb(TTA),Phen on Eu(III) caused by intermolecular energy transfer in the films was suggested.