Abstract: To study the adaptability of anti-reflection film in tropical marine environments and the protective effect of a waterproof layer on the film, two kinds of germanium-coated infrared antireflection film samples, with and without a waterproofing layer, were put into a tropical marine environment for natural exposure test under the shed. By observing and detecting the morphology, structure, composition, and transmittance of each cycle test sample, the failure mode, damage process, and change in transmittance were analyzed. The results show that the membrane was not damaged during one cycle under the shed. After two cycles, pitting occurred at the edge of the film layer, and the degree of corrosion became severe with an increase in test time, gradually extending from the edge to the center of the sample. After four test cycles, the edge corrosion of the samples without the waterproofing layer was more severe, and the corrosion of the samples with the waterproofing layer was lighter. The transmittance of the samples at 3.7–4.8 μm did not decrease, showing better adaptability to the tropical marine environment.