Abstract: In this paper, a preliminary stress/strain analysis of the design structure of a nitinol patent foramen ovale occluder is carried out. In the analysis, solid structure modeling was carried out for three different specifications patent foramen ovale occluders. Referring to the test method of fatigue performance in YY/T 1553−2017, the initial installation deformation was applied to the model, and then the fatigue displacement of 2 mm was applied to the sample to make the model fatigue deformation. The fatigue safety factors of each type of occluder were obtained by strain simulation analysis. The results indicated that the minimum fatigue safety factors of the three specifications patent foramen ovale occluders are 2.09, 2.35 and 2.06, which meet the design of fatigue safety factor greater than 1. Among them, 1818 and 3030 specifications have similar values, and both are lower than the specifications of 1825 model. Therefore, it is recommended to carry out physical fatigue test on both 1818 and 3030 specifications to further verify the fatigue performance of the products.