The invention discloses a combined mechanical ventilation fermenting and drying dual-purpose tank. The combined mechanical ventilation fermenting and drying dual-purpose tank comprises a bearing mechanical ventilation device, a temperature regulation automatic control device and an indoor-temperature heating device which are installed in a fermenting and drying chamber. The bearing mechanical ventilation device comprises a ventilation tank and an electric fan, the ventilation tank is formed by two long-side biconvex plates, two wide-side biconvex plates and the like in a combined and spliced mode and is supplied with air through the electric fan. An intelligent temperature regulation instrument in a distribution box of the temperature regulation automatic control device is connected with the electric fan and an electromagnetic steam regulation valve. The indoor-temperature heating device is composed of a central heating introduction air inlet pipe through the electromagnetic steam regulation valve, steam pipelines, steam stop valves, steam heat radiation fins and steam trap valves. The combined mechanical ventilation fermenting and drying dual-purpose tank is simple in structure, reasonable in design, capable of achieving two proposes and saving labor and time, convenient to operate, high in production efficiency, and capable of well achieving the purposes of fermenting and drying yeast materials and bringing great advantages to product transport and the price.