The invention relates to a constant-temperature and constant-humidity fermenting box. The fermenting box comprises a box body, a transmission device, a sterilizing device, a heating device, a humidifying device and a control center, wherein a first push-pull window is arranged at the upper part of the left side of the box body, a second push-pull window is arranged at the lower part of the right side of the box body, box doors are arranged on the front side of the box body, observation windows are arranged on the box doors, a drain valve is arranged at the bottom of the box body, and an exhaust hole is formed in the bottom of the box body and is communicated with the drain valve; the transmission device is mounted in the box body and comprises a motor, a transmission gear set, a series of transmission gears and a series of transmission chains, the transmission gear set is connected with the motor, and the transmission gears and the transmission chains are matched with each other; the heating device comprises an air filter screen, an air blower, a fan cover, heating wires, a partition board and a temperature sensor; the humidifying device comprises a moisture generator, a water tank, a moisture atomizer and a humidity sensor. Fresh wet noodles fermented by the constant-temperature and constant-humidity fermenting box are adequately fermented and are bright in color and long in shelf life, and the chewiness of the noodles is enhanced.