The invention discloses a transmission belt fireproof method and structure. The structure comprises an upper layer transmission belt, a lower layer transmission belt and a transition transmission belt; the transition transmission belt penetrates from a door opening of a fireproof door, the upper end of the transition transmission belt is in hinged connection to the end of the upper layer transmission belt, the lower end of the transition transmission belt is in lap joint with the lower layer transmission belt, and the upper layer transmission belt and the lower layer transmission belt are connected together through the transition transmission belt; the lower end of the transition transmission belt is fixedly connected with one right-angle edge of a right-angle lock part, the other right-angle side of the right-angle lock part is connected with a first spring, a first hook is arranged at the corner of the right-angle lock part, and an L-shaped lock part is arranged below the right-angle lock part; and when the fire disaster happens, the transition transmission belt can be rapidly broken off from a transmission belt, it is ensured that the fireproof door smoothly descends and is closed, a channel between houses is blocked, and therefore the fire spreading is avoided, and economic losses and casualties are reduced.