Abstract: Improving the efficiency of fertilizer use is an important way to promote a reduction in fertilizer use, and agricultural digitalization provides a new perspective for continuously improving fertilizer use efficiency. Based on panel data from 30 provinces (cities, autonomous regions) in China from 2012 to 2021, this paper uses the non-expected output SBM model with global reference and entropy method to measure the efficiency of fertilizer use and the level of agricultural digitalization. On this basis, the paper uses panel Tobit model and mediating effect model to empirically analyze the impact of agricultural digitalization on fertilizer use efficiency and its path of action. The results showed that agricultural digitalization has developed rapidly in China since 2019, but there are obvious regional differences in development level, with the eastern region being higher than the national average and the middle and western regions being lower; the benchmark regression results showed that agricultural digitalization significantly improves fertilizer use efficiency at the 1% level, and the conclusion remains valid after the endogeneity treatment and robustness test; the mechanism test showed that agricultural digitalization improves fertilizer use efficiency by expanding the scale of agricultural land operation, promoting the development of agricultural socialized services, and using green technologies; the heterogeneity analysis showed that agricultural digitalization has a significant positive impact on fertilizer use efficiency in non-grain producing areas and western regions, but has no significant impact in grain producing areas, the eastern and central regions. Therefore, we should continue to play a positive role in improving fertilizer use efficiency through agricultural digitalization, promote the transformation of agriculture in rural areas, improve the platform of land transfer market, promote the development of agricultural socialized services, strengthen the promotion and training of green technologies, and provide impetus for better playing the mediating.