Abstract: Deposit metal samples are prepared by GMAW shielded with different gases in copper mould with water cooling. The diffusible hydrogen and the hydrogen embrittlement sensitivity of the samples are investigated by measuring the diffusion hydrogen amount and the crystalline fracture area in breach steady bending test, and the microstructure is also investigated under SEM. The result indicates that the shielding gas constituent can change the inclusion distribution and the microstructure of the weld as well as the hydrogen embrittlement sensibility of the weld metal.