The utility model discloses a multi -field coupling experimental apparatus is piled to grain in bulk, including upper shed model box, be provided with temperature, humidity transducer in the box, preceding, the back lateral wall of model box are provided with the observation window, the left and right lateral wall of box is the cavity structure, arranges the circulating pipe who is linked togetherwith outside height, low temperature control system in it respectively, and the box opening part is provided with servo flexible loading control system: this system is including withholding the apronat the box opening part, and apron level down is provided with pressure airbag, and the gasbag is issued and is equipped with pressure sensor. The utility model discloses simple structure, convenientoperation, the degree of accuracy is high, adopts the model box of filling grain as a certain concrete position in the granary, through pressure control system, temperature control system, ventilation control system, visualization window, and infrared hot digital image and sessile drop method, multinomial measure mutually combines, has realized grain in -pile pressure field, temperature field, moisture field, the research of air flow field's multi -field coupling law a little.