Abstract: Nitrous oxide (N₂O) emission from agriculture is a major driver of global warming. Biochar is considered a promising solution due to its dual potential to reduce N₂O emissions and enhance soil carbon sequestration. Many meta-analysis studies have investigated the effects of biochar application on N₂O emissions and its mitigation potential. However, no systematic studies have been conducted to explore its effects on the N₂O emission factors. This study established the N₂O prediction models using meta-analysis combined with machine learning methods, and identified key factors influencing the N₂O emission factor, such as biochar feedstock type, carbon-to-nitrogen ratio (C/N), application rate, soil cation exchange capacity (CEC), and nitrogen application rate. Although the impact of biochar from different sources on N₂O emissions in wheat or maize fields was relatively small (wheat season: 0.032 - 0.037; maize season: 0.023 - 0.024), an appropriate biochar production temperature (500 - 600°C) and application rate (25 - 30 t hm⁻²) could reduce N₂O emission coefficients by 40.1% - 59.0% for both wheat and maize seasons, with the most significant mitigation effects observed in loam and sandy loam soils. In summary, establishing precision N₂O emission factor prediction models may effectively capture the influence of biochar properties, management practices, and environmental conditions on N₂O emissions in wheat and maize fields, and suggest suitable recommendations for biochar application. These findings provide important technical support for the rational application of biochar in wheat-maize rotation systems to reduce N₂O emissions from farmlands.