The hydrogen permeation behavior of X80 pipeline steel with different thicknesses was studied by means of electrochemical hydrogen permeation test, and the influence of hydrogen pre-charging time on the mechanical properties of X80 pipeline steel was also assessed via slow strain rate tensile test. Meanwhile, finite element analysis was used to simulate hydrogen concentration within the steels, which were hydrogen pre-charged for different times. The results indicate that as the thickness increases, the steady-state current density and steady-state hydrogen permeation flux of X80 pipeline steel decrease. Moreover, the penetration time and lag time of hydrogen diffusion increase, suggesting that the increase in steel thickness enhances both the quantity of hydrogen traps and the pathways for hydrogen diffusion of the steel. Additionally, pre-charging time significantly impacts the susceptibility to hydrogen embrittlement of the steel, resulting in a slight increase in yield strength and a notable decrease in elongation with the increasing pre-charging time. Macroscopic and microscopic fracture surface analyses reveal that steels subjected to in-situ hydrogen charging exhibit distinct brittle fracture characteristics. As the pre-charging time increases, the ductile fracture features diminishing, while the number of secondary cracks increased gradually, which may be attributed to the increased concentration of hydrogen atoms within the steel. The fitting results show that the internal hydrogen concentration is negatively correlated with the elongation and positively correlated with hydrogen embrittlement sensitivity.