The invention discloses a connecting piece for a rotor wing of a rotor tower of a helicopter. The connecting piece for the rotor wing of the rotor tower of the helicopter comprises a guide drum supporting seat, a spline flange, a rotor wing shaft and a cone-shaped ring assembly. The spline flange with openings at the two ends and a hollow inside is arranged in the guide drum supporting seat. One end of the rotor wing shaft extends into the guide drum supporting seat, the rotor wing shaft is arranged in the spline flange and matched with the spline flange in a transmission mode, and the other end of the rotor wing shaft is used for being connected with the rotor wing. The cone-shaped ring assembly is arranged on the periphery of one end of the spline flange and connected with the rotor wing shaft. The cone-shaped ring assembly is provided with a cone-shaped outer wall, the inner side of the cone-shaped outer wall is attached to the rotor wing shaft, and the outer side of the cone-shaped outer wall is attached to the inner wall of the spline flange. According to the connecting piece for the rotor wing of the rotor tower of the helicopter, the cone-shaped ring assembly is added and used for ensuring that a rotary shaft and the rotor wing shaft are coaxial.