The utility model provides an automobile back spare door inner panel, includes reinforcing frame, separate into the bearing structure of first framework and second framework with reinforcing frame, first framework and second framework all include base, side and topside, bearing structure and base, side and topside enclose close form one in the cavity, and locate the first strengthening rib and thesecond strengthening rib of cavity intracavity, and first strengthening rib and second strengthening rib are connected and divide well cavity into three region or four regions, and first strengthening rib has at least one end to connect in perhaps topside and bearing structure's handing -over department of handing -over department of base and side. The automobile back spare door inner panel thatthis embodiment provided passes through bearing structure and separates into first framework and second framework with reinforcing frame to set up first strengthening rib and second strengthening rib,first strengthening rib has at least one end to connect in handing -over department of base and side or topside and bearing structure's handing -over department, effectual lateral rigidity, torsionalrigidity and the mode performance that improves car door inner panel, thus further promoted the NVH performance of car.