The invention discloses a fabric reel clamping mechanism of a jig dyeing machine. The fabric reel clamping mechanism comprises a shell and a fabric reel shaft. Transmission shafts are hinged to the two lateral walls of the shell. A slot is formed in one end face extending into the shell. The upper end of the slot extends out of the upper lateral walls of the transmission shafts. The bottom end of the slot is provided with an extending hole. The top surface of the extending hole is provided with a thread-connection through hole. A locking ball plunger is connected into the thread-connection through hole in a threaded manner. The steel ball of the locking ball plunger extends into the extending hole. Ball plungers are connected to the two lateral walls of the slot in a threaded manner. The steel balls of the ball plungers extend into the slot. The end of the fabric reel shaft is provided with an insertion part which is nested into the slot. The lateral wall of the insertion part is provided with recessed holes, and the steel balls of the ball plungers are nested into the recessed holes. The fabric reel clamping mechanism is simple to manufacture, convenient in connection, convenient to mount and demount and high in efficiency.