A heterogeneous Fenton catalyst was prepared for the removal of organic pollutants from dye wastewater by using reductive organic acids coupled with iron ions supported activated carbon fiber. The in-situ reduction of Fe3+ to Fe2+ was promoted by the strong reducibility of reducing organic acids. The organic pollutants can be effectively enriched and degraded due to the high adsorption and good conductivity of activated carbon fiber. SEM, FT-IR and ICP-AES were used to characterize the prepared ferric oxalate supported activated carbon fiber (Oxa-Fe/ACFs-3). It was proved that the ferric oxalate complex was uniformly loaded on the activated carbon fiber, and the mass fraction of iron was 0.96%. The degradation of dye wastewater by activating H2O2 with Oxa-Fe/ACFs-3 showed that the chemical oxygen demand (COD) removal of wastewater can achieve 62.2% within 100 min at 50 ℃. In addition, the suitable pH range and reusability of the catalyst were investigated. Electron paramagnetic resonance (EPR) experiments showed that Oxa-Fe/ACFs-3 promoted the activation of H2O2 to generate active radicals •OH and O2•-, which realized the degradation of organic compounds in dye wastewater. By comparing the performance of different reducing organic acids complexed with ferric supported activated carbon fiber in the treatment of dye wastewater, the enhancement of reducibility of organic acids is beneficial for the removal of COD in dye wastewater.