Eu(TTFA)₃-doped resin photoresist polymer film was successfully prepared and the fluorescence properties of the chelate complex were investigated. Based on Judd-Ofelt theory,the optical intensity parameters Ω₂ and Ω₄ derived from the emission spectrum were 24.4×10^-20 cm² and 2.8×10^-20 cm2,respectively,and the total radiative transition rate (977 s^-1) along with the radiative lifetime (1.02 ms) of the 5DOI0 excited state were calculated.The stimulated emission cross sections σ and the fluorescence branch ratios β for the 5DOI0→7FJ(J=1, 2,4) transitions were also obtained.The analysis indicates that the excited state of Eu³⁺ in the polymer film has a long radiative lifetime and large emission cross section,and the photoresist polymer film is a kind of ideal active amplificatory waveguide material,whose emission wavelength is in accord with the low absorption loss region of the photoresist.Such photoresist polymer film might have extensive application prospect in optical devices,such as polymer optical waveguide amplifiers and lasers.