Abstract: In this study,plasma electrolytic oxidation treatment was performed on TA1 titanium alloy in silicate electrolyte doped with graphene oxide (GO) to obtain high hardness plasma electrolytic oxidation coating (PEO). The effect of GO concentration on coating properties was analyzed by characterizing the phase composition,surface and cross section morphology,roughness,microhardness,friction coefficient,and binding force of the coating. The results showed that GO participates in the coating formation process,which can effectively reduce the size of micropores and cracks,and reduce the surface roughness. Although the coating thickness decreased slightly,the density increased significantly. Compared with the non-doped GO PEO coating,the PEO coating with GO doping at a concentration of 0.6 g·L^-1 had an increase of 18.54% in the microhardness,a decrease of 84% in the friction coefficient,and an increase of 32.59% in the critical load strength.