<p>To address the challenge of reliability assessment for wind turbine gearboxes under the combined effects of performance degradation and extreme weather, this study proposes a competing failure reliability assessment method based on the degradation values distribution. Firstly, a natural degradation model for the gearbox is developed using the degradation values distribution. Then, considering the interdependence between the degradation process and shock events, a competing failure model is established by incorporating dynamic variations into both the safety threshold and the hard failure threshold to effectively estimate the reliability of wind turbine gearboxes subjected to both natural degradation and random shocks. Finally, case studies are conducted to compare the reliability obtained by competing failure models with varying rates of safety threshold and hard failure threshold degradation. The results demonstrate that the proposed competing failure model achieves precise classification of individual shock events and improves the accuracy of reliability assessments by accounting for the time-dependent degradation processes of both the safety threshold and hard failure threshold.</p>