To use sugar beet pulp as a high-effective catalyst for the degradation of dye wastewater, de–pectinated sugar beet pulp(DSBP) was modified using citric acid to introduce the carboxyl groups, citric acid-esterification sugar beet pulp fiber (CDSBP) was coordinated with Fe3+ ions to produce carboxylic fiber Fe(CDSBP-Fe). The surface morphology and chemical structure were characterized by FTIR, XRD, and SEM. Then, the catalytic performance of CDSBP-Fe was evaluated as heterogeneous light Fenton catalysts for oxidative degradation of reactive red 195. The results show that the carboxyl groups have been introduced into surface structure of fiber by ester linkage with citric acid and coordinated with Fe3+ ions to prepare carboxylic fiber Fe. The degradation of azo dye was significantly accelerated by the presence of CDSBP-Fe under visible irradiation, and the degradation rate was up to 95.6% after 25 min; CDSBP-Fe showed good degradation performance in the pH range of 3~9. Additionally, no significant catalyst deactivation was noted after five succesive runs.