Abstract: In order to investigate the surface nanostructures induced by helium plasma on tungsten surface, tungsten samples were exposed to low energy (40 eV) and high flux (4×10²³ m^-2•s^-1) helium plasma at 673 K in Pilot-PSI linear plasma device of Dutch Institute for Fundamental Energy Research. Experimental results show that after exposure to helium plasma, surface nanostructures with different morphologies appear on tungsten surface, and the surface nanostructures show strong dependence on the surface normal direction. Triangular structures are observed on surfaces with 111 surface normal direction, and lamellar structures are observed on 110 surfaces, while no obvious structures are observed on 001 surfaces. The lateral sizes of nanostructures are about 50 nm, and the height of surface nanostructures is lower than 5 nm. In addition, fluctuations appear along the grain boundaries, and the height difference of which is about 25 nm. The surface morphology on tungsten surface is speculated to be due to the helium bubbles in the near surface region.