Complex of europium with 5-aminoisophthalic acid was synthesized in the aqueous solution. The complex has bright red light when excited by UV light. UV-Vis absorption spectra of the complex show that the UV absorption is mainly from the ligand. FTIR spectra indicate that in the complex Eu3+ was coordinated with carbonyl oxygen in the form of bidentate chelate. And excellent fluorescence property is confirmed by the fluorescence spectrum. Optimal excitation wavelength is 395 nm, and the emission spectrum is the characteristic spectrum of Eu3+; there is a sharp and strong red peak with 7 nm mid-width at 616 nm, which is attributed to 5D0→7F2 transition from Eu3+ ions; Eu3+ exists in the site without inversion symmetrical center. Meanwhile, the fluorescence spectrum of the complex reveals the M-M fluorescence mechanism