Abstract: Maize is one of the main grain crops in China, which is rich in various vitamins and other nutrients.The influences of extraction time, treatment temperature, solid-to-solvent ratio and activated carbon load on the extraction of folic acid were investigated by the single factor experiments and detected by high performance liquid chromatography.By Box-Behnken methodology, the extraction conditions were optimized as follows:extraction temperature 42℃, solid-to-solvent ratio 1:11.7 (g/mL), extraction time 7.3 h and activated carbon load 1.2 g.Three parallel experiments were performed under the optimized conditions, and the content of folic acid in maize was 1.68±0.05 μg/g.Results also indicated that, among the four factors, the effect of temperature was the most significant.These can provide the available information for the study of folic acid content in main grain crops.