Abstract Electrochemical hydrogen charging was performed on a 30CrMnSiNi2A steel tensile sample, and the difference in hydrogen-charging effect with different hydrogen-charging times, current densities, and toxic agents was compared. The effect of hydrogen on the tensile strength, elongation and failure mode of the material was studied by the tensile test of slow strain rate. Results of the test show that hydrogen can greatly reduce the tensile strength, plastic deformation capacity, and elongation of 30CrMnSiNi2A steel, and the higher the hydrogen concentration in the material is, the more obvious the reduction will be. Hydrogen can make the failure mode of 30CrMnSiNi2A steel change from ductile failure to quasi-joint fracture and intergranular fracture.