Abstract: In this paper, slow strain rate tensile, fracture toughness and gas phase hydrogen penetration tests were conducted on the X52M base metal and girth welds under a simulated hydrogen-doped environment with a total pressure of 6.3 MPa and 30% hydrogen concentration. The degradation of the test steel's performance in the hydrogen-doped environment was analyzed. Results show that the mechanical properties of the test steel base metal and girth welds are inferior to those in the air environment at a total pressure of 6.3 MPa and 30% hydrogen ratio. Through analyzing the hydrogen sensitivity of different mechanical properties, it is proposed that notched tensile strength loss, the proportion of tough fracture area, and crack tip opening displacement be combined to evaluate the applicability of pipelines in hydrogen-doped environments.