Understanding the response of intercropped maize root architecture, arbuscular mycorrhizal fungi (AMF), and nitrogen accumulation and nutrient absorption to nitrogen fertilizer application is crucial for maintaining the stability of farmland ecosystems. A pot experiment was conducted with four nitrogen application rates (0 mg/kg [N₀], 85 mg/kg [N₁], 170 mg/kg [N₂], and 255 mg/kg [N₃]) and two planting patterns: monoculture maize (MM) and intercropped maize (IM). The study measured various root architectural parameters including total root length (Rl), total root surface area (Rsa), total root volume (Rv), average root diameter (Mrd), and root tip number (Tips), as well as AMF infection rate (AMF%) and nitrogen accumulation in plants. The correlation between nitrogen application rates and the root architecture, AMF%, and nitrogen accumulation in maize was analyzed. Key findings are summarized as follows:Nitrogen application significantly enhances the root architecture of maize. Specifically, under the N₂ nitrogen application rate, both intercropped and monoculture maize exhibited optimal root architecture. Compared to monoculture, intercropped maize showed improved root architecture, with Rl and Mrd increasing by 9.34% and 12.08%, respectively, at the N₂ rate. The AMF% of both intercropped and monoculture maize initially increased and then decreased with increasing nitrogen application rates. Notably, under N₁ and N₂ rates, the AMF% of intercropped maize increased by 15.2% and 17.2%, respectively, compared to monoculture maize. Nitrogen accumulation in maize also increased significantly with higher nitrogen application rates. Under N₁, N₂, and N₃ rates, the nitrogen accumulation in all parts of intercropped maize was significantly higher than that of monoculture maize, with average increases of 18.22%, 19.34%, and 18.38%, respectively. There was a positive correlation among AMF%, root architecture, and nitrogen accumulation in both intercropped and monoculture maize. In conclusion, intercropped maize demonstrated significant advantages under the N₂ nitrogen application rate. At an appropriate nitrogen application rate, mycorrhizae and roots can more effectively promote nitrogen accumulation in maize, thereby enhancing the benefits of intercropping.