[Objective] Combined application of chemical fertilizer and biochar is one of the important procedures to improve the nitrogen fertilizer utilization rate (NUE) of crops, but the nitrogen fertilizer utilization rate of crops is affected by factors such as region, soil properties, biochar properties, and biochar and nitrogen fertilizer application rates. Since most of the current research is only carried out under certain conditions, the impact of biochar on the utilization rate of nitrogen fertilizer is a lack of systematic analysis and comparison. Therefore, this article explores the impact of biochar on nitrogen fertilizer utilization, quantifies the impact of biochar on crop nitrogen fertilizer utilization under different soil and biochar application rates, and guides the use of biochar to provide an important basis for improving nitrogen fertilizer utilization. [Method] In this study, 33 publicly published documents were collected, and 170 sets of nitrogen fertilizer utilization data including biochar combined with chemical fertilizer (NPK+BC) and single chemical fertilizer (NPK) treatment were established, and integrated analysis (Meta- analysis) to study the differences in nitrogen use efficiency in different regions under NPK and NPK+BC treatments. [Result] Generally speaking, the application of biochar can improve the nitrogen fertilizer utilization rate of crops, which is increased by about 4.76%. Among them, the effect of increasing nitrogen fertilizer utilization rate in the southern region is the most obvious. In the southern regions with acid soils and nutrient deficiency, the application of potassium and phosphate fertilizers should be increased in conjunction with biochar to improve the nitrogen fertilizer utilization rate of the crops; in the northeast region of fertile nutrients, the application of nitrogen and organic fertilizers should be controlled to maximize the effect of nitrogen fertilizers. The application rate of biochar should be controlled at about 1~ 3%. When the application amount of nitrogen fertilizer is less than 120kg.hm^-2, the synergistic effect of biochar is the most obvious. Secondly, in terms of physicochemical properties of biochar, biochar made from wood materials can increase the nitrogen fertilizer utilization rate by 7.99%; when the nitrogen content of biochar > 2%, the synergistic effect of nitrogen fertilizer utilization rate reaches 19.43%; the biochar pH is From 9 to 10, the increase in nitrogen fertilizer utilization rate is the most obvious, reaching 5.01%. Finally, the synergistic effect of food crop biochar is better than that of economic crops, and the synergistic effect of field trials is better than pot experiments. [Conclusion] The application of organic fertilizers and nitrogen fertilizers should be reduced and the cultivation of nutrients should be controlled in the northeast region where nutrients are distributed; in the southern regions with poor nutrients, attention should be paid to increase the pH of the soil and increase the application of potassium and phosphate fertilizers to more effectively use biochar For the synergistic effect of nitrogen fertilizer utilization rate and the effect of increasing yield and efficiency, the application amount of biochar and nitrogen fertilizer should be formulated according to the local soil properties. Secondly, for the selection of biochar, we should pay attention to comprehensive factors such as raw materials, application amount and nitrogen content, and select the best preparation materials.