Abstract: In view of the low efficiency and poor catalytic activity of 4-nitrophenol (4-NP) catalysts for degradation of industrial wastewater, eucalyptus wood bleaching chemical pulp was used as the raw material and treated with ultrafine grinder and high pressure homogenizer to produce cellulose nanofiber (CNF) with the diameter of 50-100 nm and the length of 1500-2000 nm. Then, copper oxide nanoparticles (CuO NPs) were in-situ loaded onto CNF, 3-chloropropyltrimethoxysilane (CPTES) and diethanolamine (DEA) were added for grafting reaction to obtain the catalytic composite of CuO NPs@CNF-Si-N(OH)₂. The catalytic composite was characterized with Zeta potential, FTIR, XRD, XPS, thermal gravimetric analysis and morphology analysis. The results show that CuO NPs are in-situ loaded on CNF, and the grafting of amine groups can make the loading of CuO NPs more uniform and stable. In addition, it is also found that CuO NPs@CNF-Si-N(OH)₂ show the optimal catalytic performance with 20wt% DEA. Furthermore, 98.39% of 4-NP is catalytically reduced after 180 s, and the reaction fit the pseudo-first order kinetics equation, in which the reacting constant reaches 5.50×10⁻³ s⁻¹ and the turnover frequency achieves 1723.24 h⁻¹. The composite catalysts of CuO NPs@CNF-Si-N(OH)₂ exhibite excellent recycling performance, and 94.42% of 4-NP can be catalytically reduced after a recycling time of 8. The results can provide a new idea and approach for the preparation of high-performance catalytic composite.