The invention discloses a tool replacing manipulator of a numerically-controlled machining center in the technical field of machine tool tool replacing equipment. The tool replacing manipulator of thenumerically-controlled machining center comprises a connecting part, tool claws, a mechanical arm body and self-locking mechanisms; the connecting part is connected with a machining center body; thetool claws are located at the two ends of the mechanical arm body; the upper surface of the mechanical arm body is provided with countersunk grooves, and the two ends of the mechanical arm body are each provided with a through hole used for containing a tool jacking rod; and each self-locking mechanism comprises the corresponding tool jacking rod used for fixing a tool, a sliding block arranged inthe corresponding countersunk groove and a locking pin matched with the sliding block. According to the tool replacing manipulator of the numerically-controlled machining center, through the interaction force of the locking pins and the sliding blocks in the self-locking mechanisms, the sliding blocks slide in the countersunk grooves and drive the tool jacking rods to move, automatic tool replacing of the numerically-controlled machining center tool is completed, the process is simple, and operation of workers is convenient; and the tool jacking rods are pushed to make contact with the tool through first springs and second springs of the self-locking mechanisms when the tool is replaced, tool falling is prevented, and safe and continuous tool replacing work is guaranteed.