The invention discloses a coupling, and relates to the field of couplings. The coupling comprises a joint body and two fixing joints; the joint body comprises an outer ring piece set and an inner ringpiece set, wherein the outer ring piece set comprises a plurality of outer ring pieces, the inner ring piece set comprises a plurality of inner ring pieces, and the inner ring piece set is arranged in the outer ring piece set in a sleeved mode; the inner ring pieces are connected to the adjacent outer ring pieces, each inner ring piece and the adjacent inner ring piece in the inner ring piece setare arranged at intervals, and each outer ring piece and the adjacent outer ring piece in the outer ring piece set are arranged at intervals; the axis of the joint body is a Z-axis, the cross sectionof the joint body is an XOY plane to establish a spatial coordinate system XYZ, and each inner ring piece and the two adjacent outer ring pieces are rotationally connected at corresponding positionsin the positive and negative directions of the X-axis and the positive and negative directions of the Y-axis respectively; and the two fixing joints are connected to the two ends of the joint body respectively, and the fixing joints are used for being connected to external components. According to the coupling, the rotary angle is high, and the transmission torque, the motion stability and the flexibility is more excellent.