A numerical investigation of natural convection flow along irregular Vertical surfaces in non-Newtonian fluids is reported. A wavy vertical surface is used as an example to show the heat transfer mechanism near such surfaces. The results demonstrate that with an increase of flow index, the axial velocity increases, but the velocity boundary layer becomes thinner. The difference between the velocity in the crests and the troughs is indiscernible. The boundary layer around nodes is getting thicker compared to that of the crests and the troughs. When the natural convection boundary layer grows thick, the amplitude of the local Nusselt number gradually decreases. The effects of Prandtl number, flow index and surface amplitude in non-Newtonian fluids are also discussed in detail.