Hastelloy-X specimens are processed and post-processed by the selective laser melting technique, the macro-/micro-structural characteristics of as-deposited, heat-treated and heat-plus-heat-isostatic-pressure-treated specimens are analyzed, and the tensile property at room/high temperature is tested, respectively. The results indicate that the micro-cracks appear at both horizontal and vertical directions of as-deposited specimens, but no precipitates occur. After heat treatments, the transverse microstructures become equiaxed grains, while the longitudinal microstructures are interleaved fine or coarse columnar grains, and within these grains, there exist two kinds of precipitates with quite different morphologies. After the hot-isostatic-pressure treatment, the grains grow up significantly, the distribution of the precipitates are homogenously distributed, and the tensile property at room temperature reaches the forging standard. The transverse tensile property is characterized by high strength and low plasticity compared to the longitudinal one.