Abstract: Understanding the wettability phenomenon and its influence factors, thus further modifying the surface wettability, are important issue in the energy engineering field. By the means of molecular dynamics simulations, the static contact angles of two-dimensional water droplet on the nano-grooved surfaces were obtained. The effects of the groove depth and hollow width on the contact angle and wetting regime under different intensities of interactions between water and surface molecules were analyzed. The results show that the nano-grooves make the surface more hydrophobic; when the groove depth exceeds a certain value, the contact angle remains insensitive to the groove depth; while increasing the hollow width, the contact angle shows a growing tendency; the changes of the groove depth and hollow width may also result in the transition of the wetting regime; moreover, the variation of the contact angle is in agreement with Cassie Baxter equation, but does not match with the Wenzel theory.