Connecting device

The utility model discloses a connecting device. The connecting device comprises a clamping piece and a connecting base, wherein the clamping piece comprises a cylindrical piece, a first stop piece, a second stop piece, a locking nut and a connecting rod, the cylindrical piece is provided with a first end and a second end which are opposite to each other, the outer surface of the first end is smooth, and the second end is a threaded surface with external threads; the first stop piece is fixedly installed on the end face of the first end of the cylindrical piece, and the second stop piece can be in sleeved connection with the smooth surface of the first end of the cylindrical piece in the mode of sliding in the axial direction of the cylindrical piece; the locking nut is in thread fit with the threaded surface of the second end, so that the second stop piece is forced to approach the first stop piece when the locking nut is rotated in the first direction; the connecting rod is connected with the second end of