Single crystal furnace

The utility model discloses a single crystal furnace which comprises a furnace bottom plate, the furnace bottom plate comprises a substrate and a lining cover connected with the substrate, and a containing space used for being filled with heat insulation materials is formed between the lining cover and the substrate; at least two first through holes are formed in the lining cover, the at least two first through holes penetrate through the lining cover in the first direction, the first direction is the direction from the lining cover to one side of the substrate, the at least two first through holes are provided with sheaths in the circumferential direction, and the sheaths stretch downwards in the first direction and abut against the substrate; the substrate is provided with a second through hole corresponding to the first through hole, and the second through hole penetrates through the substrate in the first direction. According to the utility model, the complex structure of the bottom of a thermal field can