The Bending stiffener is key accessory for protecting the flexible cables for offshore installations such as floating wind turbines. The bend stiffener has interface connection structure composed of a metal insert and a polyurethane part. Aiming at the problem that fatigue damage occur there, this paper proposes a fatigue analysis process for flexible cable bending stiffener which considers the interface connection structure. In order to analyze the influence of the interface connection structure on the fatigue stress and strain distribution of the bending stiffener, a numerical model considering the interface connection structure and a simplified numerical model excluding it were established according to the analysis process, and fatigue damage analysis was conducted. Then, the influence of the interface connection structure is discussed in detail, and the fatigue damage of the bending stiffener's main body , the polyurethane part of the interface connection structure, and the metal insert part of the interface connection structure are compared. The results show that the bending fatigue analysis considering the influence of interface connection structure is conducive to obtaining more safer design results for the bending stiffener. At the same time, it was found that the polyurethane part of the interface connection structure would first undergo fatigue failure.