Abstract: By an electrochemical method of Devnathan-Stachurski, hydrogen permeation(D) and hydrogen content(C₀) in L245 pipeline steel during cathodic charging with hydrogen were measured, and the effect of inhibitor CT2-19 for L245 pipeline steel hydrogen permeation was evaluated. Experimental results showed that during dynamically charging with hydrogen of L245 pipeline steel in field simulation solution, the concentration of diffusible hydrogen(C₀) is directly proportional to cathodic current(I), i.e, C₀ =0.63+0.12 I; inhibitor CT2-19 is a good inhibitor for inhibiting hydrogen permeation at the experimental concentration.