The invention discloses an agricultural fermentation reaction device. The agricultural fermentation reaction device comprises a shell, a base, a motor and a feeding hopper, wherein the shell is fixed to the base, and rolling wheels are fixedly mounted at the lower side of the base; stirring blades are fixed to the side wall of a stirring shaft; a horizontal foam breaker is fixed above the stirring blades; a glass window is embedded on the side wall of the shell; a communicating pipe extends in a water tank, and an atomizer communicates with the other end of the communicating pipe; a mounting plate is rotatably mounted on a bracket through a rotation shaft, and a plurality of vertical vacuum tubes are mounted on the mounting plate. For the agricultural fermentation reaction device, the arranged vacuum tubes heat by utilizing the solar energy, so that the water in the water tank is heated and utilized by the atomizer, the water is atomized to form water vapour which enters in the shell, thus the inside humidity is guaranteed, heat is provided for the inside, the energy consumption in heating tubes is reduced, the fermentation rate is improved, and the fermentation time is shortened; the glass window on the side wall of the shell can be directly irradiated by the sunlight, so that the inside temperature rises, and the energy consumption is reduced.