The present invention provides a use of herb ferment for preparing a composition for preventing and/or treating obesity; wherein, the herb is Abelmoschus esculentus. The fermentation process of the present invention can enhance the content of total polysaccharide in the herb ferment, and effectively increase the amylase inhibition rate and the glucosidase inhibition rate of the herb ferment to effectively inhibit the decomposition and absorption of starch and glucoside. The herb ferment of the present invention can also effectively reduce the blood glucose of subjects after meals, and can effectively reduce the body weight, BMI value, waist circumference, visceral fat, average whole body fat percentage, and average body fat percentage, and can be effectively used to regulate blood glucose and blood lipids for weight loss. The herb ferment is prepared by fermenting the herb extract to yeast and lactic acid bacteria.