Grain-refined materials are expected to accommodate numerous point defects in their grain boundaries (GBs). To know the response of grain-refined tungsten (most grain sizes < 100 nm) to helium plasma exposure, their surface morphology changes and helium bubble distributions inside the material have been observed. Experimental results show that when exposure temperature and plasma fluence increase, both grain-refined and coarse-grained tungsten undergo similar surface morphology evolution, with surfaces transiting from originally polished state to hill and valley structures, and eventually to fuzz formation. Further characterization analysis indicates no preferential GBs segregation of helium bubbles and shallow distribution depths of bubbles, which could be responsible for similar surface morphology evolution between grain-refined and coarse-grained tungsten.