The invention discloses a first-stage seed fermentation tank, which comprises a bracket, the upper end of the bracket is fixedly installed with a jacket cylinder body, the inner cavity of the jacket cylinder body is fixedly installed with an inner tank cylinder body, the upper end surface of the inner tank cylinder body and the inner tank body A stirring system is fixedly installed in the center of the inner cavity of the tank cylinder, the first compressed air connection pipe and the discharge connection pipe are arranged on the side upper end of the inner chamber cylinder body, and the steam connection pipe, the breathing pipe connection pipe and the washing pipe connection pipe are provided on the jacket cylinder body; A second compressed air connection and a material connection are installed on the other side of the upper end surface of the inner tank cylinder, and a pressure detection connection is provided below the second compressed air connection. The first-level seed fermentation tank fully ensures that the seed fermentation is in a stable environment and improves the quality of seed fermentation by setting steam connection pipes, breathing pipe connection pipes, washing pipe connection pipes, material connection pipes, pressure detection connection pipes, sampling valve connection pipes and thermometer blind pipes. , and it is easy to clean, which facilitates the fermentation of the next batch of seeds and improves the efficiency of production.