This work aims to study the effect of the coupling action between the marine atmospheric environment and tensile fatigue load on the corrosion damage behavior of 30CrMnSiNi2A steel. The test environment was the humid and hot marine atmospheric environment of the Wanning test site in Hainan. The coupling test of marine atmospheric environment and tensile fatigue load for 30CrMnSiNi2A steel was carried out for the first time with the coupling test equipment of marine atmospheric environment and tension, compression and bending loads. The effects of the coupling action of marine atmospheric corrosion and tensile fatigue load on corrosion morphology, corrosion products, tensile properties and fracture morphology of 30CrMnSiNi2A steel were studied by metallographic microscope, coupling test equipment and environmental scanning electron microscope. The corrosion characteristics of 30CrMnSiNi2A steel in the static exposure test and the coupling test were pitting corrosion. The maximum corrosion depth of the static exposure test for 1 year and the coupling test for 35 days were 95 μm and 54 μm respectively. In the static exposure test for 1 year, the tensile strength, proof strength plastic extension and percentage elongation after fracture of 30CrMnSiNi2A Steel decreased by 6.6%, 6.5% and 31.0% respectively; in the coupling test for 35 days, the tensile strength, proof strength plastic extension and percentage elongation after fracture of 30CrMnSiNi2A Steel decreased by 11.0%, 11.4% and 34.5% respectively. The results of fracture morphology showed that the extending zone near the crack source in the coupling test of 30CrMnSiNi2A Steel was quasi cleavage morphology, and there were small secondary cracks. The cracks of 30CrMnSiNi2A steel in the coupling test extended from the fatigue source to the core, forming directional corrosion fatigue damage. The results showed that the descending rate of tensile properties of 30CrMnSiNi2A steel was accelerated by the coupling action of marine atmospheric corrosion and tensile-compressive fatigue load. And the acceleration ratio of the coupling test was about 10 times that of the static exposure test.