An elastic base structure and a piece of upholstered furniture therewith. The elastic base structure includes a base frame comprising a pair of first support rods and a pair of second support rods connected to the pair of first support rod to form a square or rectangular structure; a plurality of serpentine springs; and a plurality of double-branched hook clips. Each serpentine spring has two oppose ends disconnectably connected to two double-branched hook clips that are in turn disconnectably connected to the pair of first support rods, respectively, such that the plurality of serpentine springs are parallel to each other.