The present invention relates to a permanent-magnet driving T-type guide slot sample control and inoculating crystal applying mechanism used for operating metal sample in the course of making suspension containerless treatment in vacuum chamber. Said mechanism includes an internal magnet and an external magnet which are respectively rotated on the internal magnet supporting cylinder and external magnet supporting cylinder and between the screw rod and handle which are connected by means of nut with T-type slot, and when operating, the handle can be turned, the screw rod can be axially moved along the T-type slot under the action of magnetic force, and rotated or contrariwise, so that it can implement inoculating crystal induction for sample and control its freezing process.