The invention discloses a prefabricated cross-shaped nested wing plate foundation which comprises a square cylinder, a conical expansion foundation, prefabricated reinforced concrete cross-shaped wing plates with square holes, a line tower supporting pin, a square hole, a cup rabbet, foundation bolts and structural mortar, wherein the square cylinder is inserted into the reserved cup rabbet of the conical expansion foundation, and a gap between the square cylinder and the cup rabbet is filled with the structural mortar; the prefabricated reinforced concrete cross-shaped wing plates with the square holes are nested on the outer side of the square cylinder in a layered mode, and the gap between the square hole and the square cylinder is filled with the structural mortar; the line tower supporting pin is fixed at the upper end of the square cylinder through the foundation bolts. The foundation is simple in structure and convenient to operate, can effectively improve rigidity in the horizontal direction and overall stability of a power transmission tower foundation, and improves bending resistance and resistance to capsizing of the power transmission tower foundation on a mountainous slope.