In this study, a pot experiment was conducted to investigate the effects of biochar (BC) added at 0.5% and 1.5% on soil profile nutrient characteristics, wheat yield and nitrogen use efficiency (NUE) under conventional N input rate (200 kg/hm²). The results showed that 0-40 cm soil organic carbon (SOC) content increased after BC application and was positively correlated with BC application rate, of which, 0-10 cm and 20-30 cm SOC contents under BC-amended treatment significantly increased by 21.1%-44.2% and 12.6%-18.4%, respectively. Compared with N fertilizer alone treatment, BC-amended treatments increased the contents of NH₄⁺-N (3.7%-49.0%), NO₃^--N (20.1%-23.7%), total N (3.4%-16.7%), and available K (3.6%-14.8%) in 0-10 cm soil. In addition, 30-40 cm soil available K contents were significantly increased with BC application by 10.2%-19.7%. Generally, nutrient content increases were higher under 1.5% BC amending treatment, except for NH₄⁺-N. However, BC addition reduced the NH₄⁺-N in 30-40 cm soil by 27.4%-32.8% and available K in 20-30 cm soil by 10.8%-12.6%, and the effects were more significant at lower BC added (0.5%) treatment. BC had no significant effect on either wheat NUE or yield, but performed a reducing potential (risk) on wheat yield. In conclusion, the responses of soil nutrients to BC addition significantly varied with BC application rate and soil profile depth.