Vertical axis wind turbine with a telescopic rotational diameter

A vertical axis wind turbine with a varying length of rotational diameter, comprising at least a central shaft extending vertically, connected at one end to a generator, a plurality of blades arranged at equal intervals on the outer peripheral side of the central shaft, a plurality of support shaft members are connected to each blade at one end, respectively, and extended towards the central shaft at the other end, a plurality of elastic telescopic assemblies are respectively provided at equal intervals on the outer peripheral side of the central shaft, wherein each of the elastic telescopic assemblies is connected to the support shaft member at one end remote from each of the blades, wherein each of the elastic telescopic assemblies is driven by a centrifugal force generated by the rotation of each blade to produce the extension of the support shaft member so that the rotation radius of each blade from the central shaft increases as the rotation speed increases, and the centrifugal force is reduced as the rotation speed of the blade decreases, resulting in that the support shaft components automatically gradually return to the original position.