Super-large-size chemical vapor deposition furnace

The invention relates to an oversized chemical vapor deposition furnace which comprises a deposition furnace body, the deposition furnace body comprises an inner container and an outer cylinder, a cavity is formed between the inner container and the outer cylinder, a deposition chamber is formed in the inner container, a heating cavity penetrating through the bottom wall is further formed in the inner container, and the heating cavity is arranged along the central axis of the inner container and coincides with the central axis of the inner container; the heating device comprises a main heating piece, a bottom heating piece and a center heating piece, the main heating piece is arranged in the cavity in the circumferential direction of the outer wall of the inner container and heats the whole furnace inner space, the bottom heating piece is arranged in the cavity in the bottom of the inner container, and bottom carbon source gas is heated through the bottom heating piece; and the central heating piece is arrang