The invention discloses a solid fermentation tank as well as a method for preparing red kojic rice by using the solid fermentation tank and a product prepared by the method, and belongs to the technical field of biological fermentation. The solid fermentation tank comprises a horizontal fermentation bucket, a temperature detecting opening, a humidity detecting opening, a pressure detecting opening, an inoculation opening, a sampling opening, a feeding hole, sight glass, an inlet pipe, an outlet pipe, a balance plate, a rolling bracket, a material baffle and an outside-bucket jacket. The method is used for preparing healthy nutritional red kojic rice by using the solid fermentation tank by the following steps: soaking materials; washing the materials; steaming the materials; cooling; separating; inoculating; mixing; keeping the temperature; keeping the humidity; fermenting; harvesting; and drying and the like. By virtue of the design of the invention, the environmental protection property, economic efficiency and stability of the solid fermentation tank as well as the homogeneity of the same batch of fermentation products are improved; the solid fermentation tank is applied to the preparation method; the preparation condition is optimized; the contents of red rice protein, red rice polysaccharide, ergosterol and amino acid in the prepared red kojic rice are respectively not lower than 3.0%, 2.0%, 1.0% and 1.0%; the limit amount of citrinin is not higher than 0.01mg / kg and the limit amount of monacolin K is not higher than 0.01%.