Combined screw pile and use method thereof

The invention relates to a combined screw pile and a use method thereof. The combined screw pile comprises a carrying pile, an intermediate pile and a drill bit, wherein one end of the intermediate pile is connected with the carrying pile, the other end of the intermediate pile is connected with the drill bit, and the intermediate pile is a screw pile with a hollow inside; an injection mechanism for pouring concrete is arranged in the carrying pile; a plurality of overflow holes are formed in the outer wall of the drill bit in a circumferential array manner, and grout outlet assemblies for blocking the overflow holes are also arranged in the drill bit; a liner pipe is arranged in the intermediate pile, and a rotating assembly for driving the liner pipe to rotate is also arranged in the carrying pile; and a stirring assembly is also arranged in the drill bit. The combined screw pile and the use method thereof have the advantages that the concrete is poured into a hole at the same time during pile pulling, and