In order to improve the wear resistance of titanium alloys, a process of oxygen-permeation & diffusion-solution (OP-DS) was developed, by which no oxide film was formed on the surface. The titanium alloy of TC11 was studied by TGA, SEM, XRD, XPS and micro-hardness tester at high temperature. The results indicate that the hardening depth and the hardness of surface layer can be remarkably enhanced, and the surface oxide film is decreased by the OP-DS process. The pre-OP treating time exhibited significant effect on the following DS treatment, even a hardened layer without oxide scale could be produced by proper combination of OP and DS. The OP-DS process was also discussed in terms of thermal diffusion mechanism.