The invention discloses a telescopic stair ramp of a staircase cargo transportation device. A left step guide rail and a right step guide rail parallel to the left step guide rail are arranged on each stair. A base plate is fixedly connected between the two upper ends of the two step guide rails, and a base plate is fixedly connected between the two lower ends of the two step guide rails. Annular limiting frames are arranged on one sides of the base plates. Stepped transmission rods penetrate through the upper limiting frame and the lower limiting frame. A vertically arranged telescopic plate is arranged between the two step guide rails of each step. The upper end of each telescopic plate is connected with horizontal sections of the step guide rails through hinges. Each telescopic plate is connected with the corresponding transmission rod. One side of the topmost step and one side of the bottommost step of each stair are each provided with a control rod, the upper control rod is hinged to the lower control rod through a bracing rod, and the control rods are hinged to the transmission rods through connecting rods. During usage, the steps can be laid into the ramp for cargo transportation by pulling the control rods, the ramp can be folded and packed up when no cargo is transported, and people walking spaces of the stairs are not occupied.