To improve the corrosion resistance of Ti6Al4V alloys in acid solution, a W-Mo co-penetrated top layer was prepared using hollow-cathode glow discharge plasma technique below the β phase transition point. The surface morphology, chemical composition and crystal structure of the coatings were determined by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray power diffraction (XRD), respectively. It indicated that a dense co-penetrated layer was produced with maximum thickness of approximately 23 μm. The layer was composed of AlMoTi2 and TixW1-x phases. The static corrosion test was conducted in acid (H2SO4 and HCl, respectively) at room temperature (RT) by using the electrochemical workstation. The results showed that the W-Mo co-penetrated layer could achieve relatively stable corrosion potential in reducing acid and the Icorr of co-penetrated layers occupy merely 1/10 and 1/6 that of Ti6Al4V substrates. In addition, there is barely any corroded product and crack on the corroded surface of co-penetrated layers, indicating no corroded shedding phenomenon occurred. So the corrosion resistance are obviously improved in the premise of keeping the basic properties of the substrate.