Bean curd is one of the most popular cooking raw materials with the widest eating scope, and has the effects of strengthening the middle warmer and benefiting vital energy. The bean curd protein belongs to a complete protein and contains eight amino acids which are necessary for the human body, and the proportion of the eight amino acids is close to the proportion needed by the human body. The conventional bean curd usually has a little bitter taste, and can cause protein indigestion if being taken too much, symptoms such as diarrhea and abdominal distension can appear, and the burden of kidneys is increased, which is not conductive to health. The invention provides a wheat bran dietary fiber bean curd and a preparation method thereof. The bean curd is made of soybeans through the processes of soaking, soybean milk grinding, filtering, soybean milk stewing, brine pouring, molding and the like. The preparation method is characterized in that 2%-4% of wheat bran water-soluble dietary fiber is added after the soybean milk stewing, and then brine pouring and molding are carried out. The bitter taste of the wheat bran dietary fiber bean curd disclosed by the invention is eliminated, and the bean curd promotes digestive absorption and has the functions of preventing constipation, reducing cholesterin, regulating blood sugar, preventing gall-stones and the like. The bean curd is in a solid state, no roughness sense exists in eating after a proper amount of wheat bran dietary fiber is added, and the bean curd is exquisite, fresh and tender, has strong palatability, and can be made into pure wheat bran dietary fiber bean curd.