Hardness and creep property of nanocrystalline Ta films were studied by nanoindentation tests. Experimental results suggested that hardness decreases with the decrement of grain size, which exhibits an inverse Hall-Petch effect. A remarkable room temperature creep behavior of nanocrystalline Ta films was revealed during indentation response. Creep stress exponent decreases with the decrement of feature scale, such as grain size and indent displacement. Grain boundary (GB) mediated process involving atomic diffusion and the emission of dislocation at GB is believed to be the dominant deformation mechanism.