Recently, bimetallic nanocomposites have been prepared and used in the fields of sensing, catalysis, energy and medicine. However, there are few reports on the preparation and application of new antimony-metal nanocomposites based on two-dimensional antimonene (AM). Herein, Sb2O3-CuO nanocomposites were facilely synthesized by using microwave-assisted heating the mixture solution of AM and Cu2+ ions and utilized for catalytic degradation of p-nitrophenol (PNP). Interestingly, in the mixed solution of AM and various metal ions (Cu2+, Co2+, Mn2+), only the mixture of AM and Cu2+ ions showed efficient fading and absorption reduction effects on PNP after being heated. A series of characterization on morphology and elemental composition confirmed that the nanocomposites obtained after microwave heating was composed of Sb, Cu, O elements (namely Sb2O3-CuO), and was a layered structure loaded with numerous irregular particles. Compared with other catalysts, the nanocomposite has higher catalytic efficiency (the rate constant of 1.07 s−1), and was capable of degrading 96 % of PNP with only 3 s reaction. Electron spin resonance spectroscopy and liquid chromatography-mass spectrometry analysis demonstrated that the copper-mediated Fenton-like reaction in the nanocomposites induced hydroxyl radicals which can efficiently attack and degrade PNP. This study presents a novel approach to the synthesis of antimony-metal nanocomposites and provides a potential solution for the treatment of organic pollutants.