The invention provides a method and device for improving the fireflooding auxiliary gravity oil-drainage exploiting effect. The device for improving the fireflooding auxiliary gravity oil-drainage exploiting effect comprises a horizontal well, a production oil pipe and a tracing pipe, wherein the horizontal well comprises a vertical section and a horizontal section which is connected with the vertical section, the horizontal section is located in an oil layer and communicates with the oil layer, and the production oil pipe and the tracing pipe are arranged in the horizontal well. The lower ends of the production oil pipe and the tracing pipe are both located in the horizontal section, and the production oil pipe and the tracing pipe communicate with the horizontal section. According to the device for improving the fireflooding auxiliary gravity oil-drainage exploiting effect, fire wires can be prevented from breaking through and entering into the horizontal section, and the fireflooding auxiliary gravity oil-drainage exploiting effect can be improved.