The utility model relates to a clamping type main shaft coupler of a ring spinning frame. Clamping shell, Clamping shell with key groove, Hexagonal socket screw, Nut and gasket, The clamping shell andthe clamping shell with the key groove form a hollow cylinder. Four symmetrical notch grooves are formed in the outer surface of the clamping shell along the two sides of the central axis of the clamping shell. Four notch grooves corresponding to the outer surface of the clamping shell are formed in the outer surface of the clamping shell with the key groove along the two sides of the central axis of the clamping shell with the key groove. The notch groove is arranged to be the width and the radian where the hexagon socket head cap screw can rotate and the nut can not rotate, the hexagon socket head cap screw is connected with the nut through the gasket, the rotational inertia of the shell clamping type main shaft coupler is greatly reduced, and the shell clamping type main shaft coupleris suitable for high-speed operation of equipment and low in energy consumption. The installation time and cost are reduced; And the structure is reliable, the bearing capacity is large, and the service life is long.