To address the treatment dilemma of HMX production wastewater characterized by complex components， high toxicity and poor biodegradability， a heterogeneous Fenton catalyst Fe_2.5Mo/AC loaded with Fe/Mo bimetals was prepared via the impregnation-high temperature carbonization method using chitosan-modified activated carbon （AC） as the carrier. The amino functional groups of chitosan were adopted to anchor metal active sites and inhibit the agglomeration of active components； meanwhile， Mo was introduced to construct a Fe-Mo bimetallic synergistic system， which accelerated the Fe³⁺/Fe²⁺ redox cycle and improved the generation efficiency of ·OH. Results showed that a stable Fe-Mo-O/N composite structure was formed inside the catalyst with uniformly distributed active sites. Batch experimental results indicated that the catalytic system was applicable to a wide pH range of 2.09-7.15. The removal efficiencies of HMX and COD reached 83.1% and 44.5%， respectively， and the B/C ratio of wastewater was increased from 0.011 to 0.367， presenting an obvious improvement in biodegradability. The optimal reaction conditions were determined as catalyst dosage of 5 g·L^-1， H₂O₂ concentration of 300 mM and reaction temperature of 25 ℃. Radical quenching experiments combined with electron paramagnetic resonance （EPR） tests verified that ·OH， ¹O₂ and ·O₂^- jointly participated in the degradation of HMX. After seven cycles of reuse， the HMX removal rate remained above 70% with extremely low metal leaching capacity. During 14 h continuous operation in the fixed bed reactor， the removal efficiencies of COD and HMX were stably maintained above 70% and 60%， respectively.