The utility model provides a coupler, this coupler includes: first connecting piece, first connecting piece is connected with the power shaft, the second connecting piece, the second connecting pieceis connected with treating the transmission shaft, flexible segment, flexible segment sets up on first connecting piece and second connecting piece for connect first connecting piece and second connecting piece. Avoided among the prior art equipment coupler as hard as crossing the big scheduling problem of damage, bearing wear and equipment vibration that causes, messenger's equipment can stabilize, lasting work.