<p>This paper prepares a Cu-containing maraging stainless steel with high resistance to hydrogen embrittlement (HE) and investigates the influence of microstructure on hydrogen diffusion and HE sensitivity. The results show that the hydrogen diffusion coefficient of the Cu-containing steel gradually decreases from 6.92 × 10^–9 to 0.84 × 10^–9&#xa0;cm²&#xa0;s⁻¹ with the increase of the aging treatment temperature. This change corresponds to a gradual increase in the content of reverted austenite and a weakening of the HE susceptibility, which is reduced from 74.4 to 30.0%. To ensure the accuracy of the hydrogen embrittlement susceptibility calculation, a repeatability test was performed following the initial experiment. The average values of the two tests were 74.4% and 30.0%, respectively (Table 5). However, due to an oversight, the abstract incorrectly reports the results of the first experiment (75.3% and 29.8%) instead of the averaged values (74.4% and 30.0%). Therefore, the values in the abstract should be corrected accordingly. Thermal desorption spectroscopy calculations and time-of-flight secondary ion mass spectrometry detection indicate a higher activation energy of hydrogen diffusion in austenite compared to Cu-rich and Mo-rich nano-precipitates, acts as irreversible hydrogen trap. In addition, by comparing the austenite content and HE susceptibility before and after the tensile test, the transformation-induced plasticity effect does not aggravate the HE susceptibility of the material due to the addition of Cu and Mo elements which increase the material's stacking fault energy and inhibit the transformation of austenite to martensite.</p> Graphical Abstract <p></p>