In order to study the influence of geogrid aging on bidirectional reinforced composite foundation, an indoor scale simulation was carried out. Geogrid was aged by a method of thermal oxidation and photooxidation first. Geogrid with different aging time was selected as the lateral reinforcement material of the bidirectional reinforced composite foundation. Settlement of composite foundation and its components (including cushion layer, pile reinforcement zone and bearing layer), geogrid strain and soil pressure around geogrid were monitored. Regular patterns of geogrid strain, stress and settlement in composite foundation were discussed. Conclusions are as follows: Settlement of composite foundation and its components, geogrid strain increased with geogrid aging time;pile-soil stress ratio under the geogrid and bearing capacity of composite foundation decreased with geogrid aging time;pile-soil stress ratio upper the geogrid was irrelevant to geogrid aging time.