<p>Ultrasonic shot peening (USP) is an advanced surface treatment technique that enhances the mechanical performance of metallic materials. This study systematically investigates the effects of USP on the hydrogen embrittlement (HE) resistance of 316L stainless steel. By varying the shot peening energy, we evaluate surface deformation, microstructural evolution, and resultant mechanical properties and these effects on the HE. In order to validate the improvement of HE resistance, mechanical tests such as SSRT and hardness tests with/without hydrogen charging conditions, and hydrogen contents are measured through TDS analyses. A finite element (FE) model is employed to predict stress distributions, and also performed to validate and quantify the effect of peening on the improvement of mechanical properties based on these experimental results. The results demonstrate that USP significantly improves HE resistance by inducing compressive stress and refining the microstructure. The validated FE model provides insights for optimizing USP parameters, highlighting USP as a promising technique for enhancing material reliability in hydrogen environments.</p> Graphical abstract <p></p>