The utility model discloses a foldable cantilever shelf which comprises more than two shelf units connected by support rods, wherein each shelf unit comprises a base (1), a supporting upright (2), more than two pairs of shelf cantilevers (3) and suspension fasteners (4), wherein the bottom end of each supporting upright is fixed on each base; the shelf cantilevers are arranged on each supporting upright in a rotating manner; the suspension fasteners are used for fixing the shelf cantilevers; the quantity of the shelf cantilevers and the quantity of the suspension fasteners are equal; each supporting upright is vertical to each base. The foldable cantilever shelf has the benefits as follows: the shelf cantilevers are arranged on each supporting upright in a rotating manner; when the shelf cantilevers stretch towards the two sides, the storing function of the shelf is achieved; when the shelf cantilevers are rotated to the vertical direction and fixed on each supporting upright through the suspension fasteners, the space between every two shelf units is completely emptied out to be used for storing goods and materials such as cable trays and transformers, so that the functions of the shelf are achieved, and the storage of various types of goods and materials can be realized under the condition that the shelf is not moved, therefore, the utilization ratio of the field is greatly increased.