Abstract: Intercropping can improve the yield and stability of crops; however, studies on the effects of nitrogen application rate on yield stability are limited. A field experiment was conducted in Zhangye City, Gansu Province, in China, from 2018 to 2021, including two nitrogen application rates (N0: 0 kg·hm⁻²; N300: 300 kg·hm⁻²) and three planting patterns maize||soybean intercropping (M||S), monoculture soybean (MS), and monoculture maize (MM). Crop yields in monoculture and intercropping system were determined. The productivity, land equivalent ratio (LER), partial land equivalent ratio (pLER), overyielding (OY), yield stability (YS), and nitrogen agronomy efficiency (NAE) were calculated. These indices were analyzed by comparing the monoculture and intercropping systems to clarify the effect of nitrogen on the yield and yield stability of M||S intercropping. The results showed that average over year, compared to monoculture, average LER value of the M||S intercropping under N0 and N300 was 1.26 and 1.17, respectively, both were above 1, indicating that there was a intercropping advantage for the M||S intercropping, and nitrogen decreased the advantage. Partial land equivalent ratios for maize (pLER_m) under N0 and N300 treatments were 0.68 and 0.82, respectively; pLER_s under N0 treatment was 0.57, while it was only 0.35 under N300 treatment. Overyielding of intercropped maize under N0 and N300 treatments were 36.88% and 64.82%, respectively, whereas soybean overyielding were 14.77% and −30.46%, respectively. Nitrogen application improved yield stability, and yield stability under N300 treatment increasd by 112.7% compared to that under N0 treatment (P<0.05). However, monoculture system exhibited 40.1% greater yield stability than that of intercropping system (P<0.05). No significant difference was observed between the yield stabilities under different nitrogen treatments in both intercropping and monoculture systems. In intercropping system, the yield stability of maize under N300 treatment was significantly higher (178.6%) than that under N0 treatmetn (P<0.05). Nitrogen had no significant effect on the yield stability of soybean. In monoculture system, the yield stability of soybean under N300 treatment was significantly higher (139.3%) than that under N0 treatment (P<0.05); nitrogen application had no significant effect on the yield stability of maize. The NAE in intercropping system was 76.7% higher than that in monoculture system (P<0.05). In summary, the main contributor to yield advantage was maize in the M||S intercropping system in the Zhangye City of Gansu Province. Nitrogen improved the yield and yield stability of maize in intercropping system, reduced soybean yield in intercropping system, and did not affect soybean yield stability in intercropping system.