Textured a-C: H films with groove patterning were prepared and their tribological properties in distilled water were investigated. In addition, the effects of spatial periods on the tribological performance of the textured films were also discussed. The morphology and structure of textured a-C: H film as well as the worn surfaces were observed by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The results showed that textured films exhibited excellent tribological performance compared to the untextured film in a water environment. The groove patterning with the spatial period of 0.3 mm showed the most effective friction reduction property, and the friction coefficient and wear rate were 0.038 and 8 x 10(-7) mm(3)/N.m, respectively, which is attributed to lower internal stress of the textured film, as well as combined effects of trapping wear debris, hydrodynamic lubrication effect, reduced friction-induced phase transformation, and less chemical reaction on the rubbed surface.