In order to explore the effect of biochar combined with nitrogen fertilizer on millet growth and soil, this research studied the effects of biochar(C0, 0 g·kg-1, C1, 20 g·kg-1, C2, 40 g·kg-1) combined with nitrogen fertilizer (N0, 0 g·kg-1, N1, 0.133 g·kg-1, N2, 0.266 g·kg-1) on soil nutrients, root millet morphology, photosynthesis, dry matter accumulation, etc., using Jingu 21 as a test material, a pot experiment to completely randomized design. The results showed that both biochar and nitrogen fertilizer significantly increased the soil nutrient content, and C2N2 processing has the largest increase. Compared with C0N0, the alkali hydrolyzed N content increased by 61.03%. Biochar has a significant promotion on Millet photosynthesis, root morphology, and dry matter accumulation. Under the same biochar level, the low nitrogen fertilizer will promote millet photosynthesis, root morphology, and dry matter accumulation, while the high nitrogen fertilizer will inhibit them. Compared with C0N0, C2N1 has the best effect in which the above-ground dry weight increases the most, with an increase by 129.24%. it summary, it can be seen that biochar and an appropriate amount of nitrogen fertilizer can improve soil nutrient status and promote dry matter accumulation in the above ground. Under the conditions in this experiment, C2N1 is the optimum combination, so the combination of biochar and appropriate amount of nitrogen fertilizer can promote millet growth, which can provide a certain theoretical basis for the yield increase of millet while reducing fertilizer usage.