In order to reduce the wind-uplifted damage of standing seam roof system (SSRS) under downburst, a method is proposed to evaluate the reliability of the SSRS under downburst in this article.Firstly, the large eddy simulation (LES) method is used to analyze the roof wind load characteristics under downburst, and the maximum wind load and corresponding distribution position of SSRS are obtained through different wind direction angle conditions.Secondly, the most unfavorable position of SSRS is selected to establish a local simulation model. The corresponding failure criterion and limit state function are derived; Thirdly, the Monte Carlo method based on Latin Hypercube Sampling (LHS-MCS) is used to evaluate the reliability of the SSRS under downburst. Finally, the analysis results are evaluated in combination with conventional wind reliability indicators and related specifications. The research results show that downbursts are more likely to cause wind-uplifted damage to the SSRS than conventional winds. At the same time, the reliability index under downbursts only meets the third-level safety level required by the specification. It is recommended to consider the impact of the downburst when designing the SSRS for important buildings.