The invention discloses a connecting device for a hidden frame glass curtain wall and an operation method of the connecting device. The connecting device includes a mounting ring and an adjusting column, a contraction ring is mounted at one end of the mounting ring, the contraction ring is composed of a fixing mounting column, an annular main body, a ratchet part and a hexagonal part, the adjusting column is provided with a threaded part, the adjusting column is connected with the contraction ring through the threaded part, a ratchet bar mounting block is mounted on one side of the adjusting column, and the ratchet bar mounting block is fixedly connected with the adjusting column; and a ratchet bar is mounted on the side, facing the mounting ring, of the ratchet bar mounting block, an adjusting groove is formed in one end of the adjusting column, a limiting block is mounted on the inner wall of the adjusting groove, the adjusting block is mounted in the adjusting groove, hinged heads are mounted on the four side faces of the adjusting block, the hinged heads are hinged to connecting rods, claw head mounting frames are mounted at one ends of the connecting rods, and claw heads are mounted on the claw head mounting frames. According to the connecting device for the hidden frame glass curtain wall and the operation method of the connecting device, a pulling rope is conveniently adjusted after being mounted, and use is more convenient.