The effect of whole millet diet on gut microbiota in subjects with mild hypertension was studied. The results of the study showed that after 12 weeks of whole millet diet intervention， the gut microbiota abundance of subjects with mild hypertension was significantly increased， while the diversity index did not change significantly. At the generic level， the relative abundance of Faecalibacterium and Lactobacillus increased significantly （P < 0.01）， indicating that foxtail millet could regulate the relative abundance of some bacteria in mild hypertension subjects. In addition， the gut microbiota imbalance state of subjects with mild hypertension， characterized by the accumulation of lactate-producing bacteria， reduction of acetate and butyrate-producing bacteria， was improved. The relative abundance of butyrate-producing bacteria increased by 20% compared with the baseline. The improvement of gut microbiota in mild hypertensive subjects provides a new ideal and direction for the mechanism study of antihypertensive effect in whole grains.