The invention relates to an interporosity flow double-distilled box structure in a fur defatting machine. A distilled box of the fur defatting machine is changed from an originally single-box structure into a double-box structure; the bottom plane of a solvent cavity of the distilled box is changed into a polygonal heating bottom plane; the top surface of the solvent cavity of the distilled box isadditionally provided with a balanced air suction port connected with a pressure one-way valve; the lower box structure is additionally provided with a lower box auxiliary heater; a connecting flangeof a cleaning door of the distilled box is provided with a discharge port of interporosity flow, the upper box and the lower box can be communicated by a pipe so that the liquid flows between the twoboxes, and the interporosity flow or discharge pipe is added with a steam cleaning function and the function of using steam to clean the solvent cavity.