The present invention belongs to the mining sector, and relates to a underground goaf filling simulation experiment device. The device comprises a goaf simulation box (1), a data collector (10), a bottom ore removal roadway (2), a filter tube (3), a simulation reservation crushed stone (4), a simulation barricade (6), a measuring cylinder (7), a piezometer tube (8), a water level indicator (9), a pressure cell (11) and a deformeter (12). The goaf filling simulation experiment device simulates actual condition of an engineering field in a laboratory to obtain experiment data such as filling body dehydration rate, shrinkage rate, filling body form, bottom ore removal roadway seepage water head, filling body lateral pressure, filling barricade pressure and filling body dehydrating amount variation so as to provide more accurate and reliable data guidance for field filling operation and provide a more practical and visual experiment device for teaching demonstration and scientific research of the goaf filling process.