The invention relates to the technical field of bicycles, and in particular to a foldable bicycle rear frame. The foldable bicycle rear frame comprises a base, an outer support frame and elastic reinforcing ribs. A quakeproof pad is movably installed on the outer side of an upper end of the base, and a connecting rod is arranged on the outer side of one end of the base, a sleeve is arranged on theouter side of one end of the connecting rod, a fixing plate is fixedly installed on the outer surface of a rear connecting frame, a night warning light is arranged on the outer side of one end of thefixing plate, a folding structure is arranged on the outer surface of the middle of the base. The foldable bicycle rear frame is provided with the shockproof pad, the folding structure and a hook, can eliminate vibration brought during a driving process, improves safety and comfort of back seat occupants, can perform strong-force folding, saves space, can be flexibly stretched and folded according to need, also ensures that the goods do not fall down, makes pulling goods faster and more convenient, is applicable to different working conditions, and brings better usage prospects.