Downdraft prevention assembly, smoke exhaust device and gas water heater

The utility model relates to an anti-downdraft assembly, a smoke exhaust device and a gas water heater, the anti-downdraft assembly comprises an anti-downdraft seat, the anti-downdraft seat is used for being arranged at the butt joint position of a smoke exhaust pipe and a smoke exhaust extension pipe of the smoke exhaust device, and at least one elastic buckle is arranged at the bottom of the anti-downdraft seat; the elastic buckle is used for being matched with an anti-disengaging part on the inner wall of the smoke exhaust pipe in a clamped mode. After the downdraft prevention assembly is respectively assembled with the smoke exhaust pipe and the smoke exhaust extension pipe, the elastic buckle of the downdraft prevention seat is positioned below the anti-falling part and is clamped and matched with the anti-falling part, so that the downdraft prevention seat can be prevented from being easily pulled out by external force, and the downdraft prevention assembly can be stably arranged in the smoke exhaust pi