Abstract: “Oxygen-free” Gd was fabricated by Hydrogen plasma arc melting (HPAM). The Oxygen concentration had a tendency of reduction compared with that done by Ar PAM. All these are attributable to the process of melting, especially the hydrogen atoms dissociated and activated in high temperature HPAM. An increased diffusion of oxygen in Gd-O solid solution to the surface is also believed to play an important role in removal of oxygen. The optical emission spectroscopy (OES) measurement is used to confirm the substances which were involved in the plasma like Ar I, Ar II and H I and some possible reactions. The effect of H with thermodynamic estimation is discussed in details.