Abstract: In order to reveal the time-varying effect of hydrogen embrittlement on the long-term safety performance of high-strength steel welded joints of bridges, the reliability evolution of joints in hydrogen environment was studied by combining test and model. Taking the cold-rolled continuous annealing martensitic high-strength steel as the object, the welded specimens simulating the actual joint stress state were prepared. The electrolytic hydrogen permeation test was used to simulate the hydrogen invasion process in different service environments. Combined with the room temperature tensile and low cycle fatigue tests, the hydrogen induced property degradation data and fracture morphology characteristics were obtained. On this basis, the time-varying attenuation model of joint resistance considering the cumulative effect of hydrogen diffusion was constructed, and the time-varying reliability analysis framework of welded joints under hydrogen embrittlement was established by coupling the random load process, and the time-varying rules of joint reliability and failure probability in different hydrogen concentration environment were quantitatively evaluated. The results show that with the increase of hydrogen intrusion, the joint strength and fatigue life decrease significantly, and the fracture transition from dimple plastic fracture to intergranular brittle fracture; The reliability analysis further revealed that the node reliability showed an accelerated decline trend with the service time, especially in high hydrogen concentration environment. The reliability was only about 0.7 after 100 years of service, and the corresponding failure probability was 24.2%; Under low hydrogen concentration environment, the reliability of the same period is maintained at about 1.5, and the failure probability is about 6.68%. The time-varying accelerated attenuation model established in this study can provide theoretical basis and data support for the life prediction and differential management of high-strength steel welded joints of bridges in hydrogen environment..