Abstract: When drilling into water layer in the lower section of the gas reservoir in offshore high-temperature gas wells, traditional solutions often involve cement plugging or casing and then perforation completion. However, those methods carry the risks of reservoir damage and production capacity below expectations. To ensure the effect of water plugging and production capacity release, an open-hole mechanical water plugging technology is developed. The lower water layer is blocked by the open-hole water plugging string, and a large flow area in the gas reservoir section is retained to achieve open-hole completion.This technology has been successfully applied to a high-temperature gas well in an offshore block. The well has been operating stably for over a year, and the gas production in the initial stage of operation exceeds the assigned production by 100%. The water production is equivalent to that of the neighboring wells, and the type is condensate water, indicating excellent production capacity release and water plugging performance. This case serves as a valuable reference and provides insightful guidance for mechanical water plugging and open-hole completion in similar gas wells.