The relationship between the tensile properties, microstructures and the macrostructure o f a complex-shaped nickel-based superalloy casting was investigated at elevated temperature. Specimens were prepared from the investment casting with/without HIP treatment. Grain size and microstructure of specimen were examined through optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that the tensile properties change remarkably although the specimens were cut from the same casting; the ultimate tensile strength (UTS) and elongation in semi-logarithmic scale of the specimens have an obvious linear relationship with grain size.HIP treatment can not only improve the tensile properties, but also increase the sensitivity o f elongation in terms of grain size, which roots from the morphology and redistribution of bifilms, 5 phase, Laves phase and /'precipitates. The present work will provide a better understanding of the local profile-property relationships of complex-shaped casting in bottom filling system and suggest that the local profile should be considered seriously in the design and manufacture of complex-shaped superalloy castings.