Intercropping research interest is increasing globally due to its contribution to agriculture sustainability, crop productivity, and soil quality. To better understand the advantageous effect of intercropping, a pot and field experiment was conducted to evaluate the impact of maize-alfalfa intercropping on the plant and soil nutrient contents under nitrogen fertilization (N0 and N1 at 2.0 g pot⁻¹ and 225.0 kg hm⁻²) in Changchun, China. The results revealed that intercropping with or without nitrogen fertilizer application significantly (p < 0.05) improved the yield, biomass dry matter and plant-soil nutrient contents. The increased yield and biomass dry matter (140.7 and 268.7 g pot⁻¹) and (38% and 25%) suggested the improved efficiency of the intercropping system with nitrogen in maize. Moreover, the nutrient concentration of maize and alfalfa such as nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), iron (Fe) and zinc (Zn) were also improved in the intercropping system under nitrogen fertilizer application. In general, the findings also indicated that maize-alfalfa intercropping with nitrogen fertilizer application significantly improved the soil-based N, P, K, and soil organic matter. The results suggest that the use of intercropping with reasonable nitrogen fertilizer application can improve the growth, yield, plant, and soil nutrient status.