The interactions between Fc(COOH)2 (λmax=255 nm) and BSA (λmax=277.5 nm) were studied by UV-Vis spectroscopy. The results showed that, there was a good linear relationship between absorbance and concentration for Fc(COOH)2 in range of 10~190 μmol·L-1 and for BSA in range of 100~1 900 mg·L-1, respectively. After the reaction of Fc(COOH)2 and BSA , λmax shifted to 275 nm to show the existing reaction. When the concentration of Fc(COOH)2 or BSA was fixed, the absorbance of Fc(COOH)2 or BSA increased with the increase of BSA or Fc(COOH)2 concentration, which showed the hydrogen bonding form between Fc(COOH)2 and BSA and the growth of molecular chain, and the increase of absorbance was attributed to the fact that bigger molecule absorbs more energy and release. Meanwhile, the stability of new formed molecule bond was affected by reaction time, after reacted for 0.1 to 24 and 96 h, the absorbance at 275 nm changed from 1.062 to 1.045 and 0.986 for Fc(COOH)2 (70 μmol·L-1) and BSA (1 900 mg·L-1), and the absorbance changed from 0.813 to 0.794 and 0.750 for Fc(COOH)2 (190 μmol·L-1) and BSA (700 mg·L-1), respectively.