Selective laser melting (SLM) is a new way to manufacture complex NiTi shape memory alloy parts and has become one of the research hotspots in the field of smart materials. In this paper, an optical microscope, a scanning electron microscope, an X-ray diffractometer, a differential scanning calorimeter, and a universal material testing machine were used to investigate the effect of hatch spacing (h) on the relative density, microstructure, phase-transformation behavior, and mechanical properties of a NiTi alloy fabricated using the SLM process. The results demonstrate that when the line energy density was within the range of 100?250 J/m, a continuous and stable single track could be obtained. As the hatch spacing decreased from 115 to 64 μm, the content of NiTi (B2) phase and the surface roughness decreased while the relative density and the transformation temperature gradually increased. The NiTi sample fabricated with h=77 μm exhibited the best overall performance. The relative density, compressive strength, and tensile strength were 98.5%, 3351 MPa, and 839 MPa, respectively. After the first compression cycle, the recoverable strain was 5.99% and the strain recovery rate was 97%. After the 10th and 20th compression cycles, the recoverable strain remained 5.77% and 5.75%, respectively.