Laser powder bed fusion (LPBF) forming of NiTi alloys deviates from the powder design composition due to the evaporation of Ni, and the properties of NiTi alloys such as the shape memory effect and superelasticity are greatly influenced by the Ni content. Therefore, it is necessary to investigate the LPBF formability, microstructure and mechanical properties of NiTi alloys with different Ni contents. In this paper, Ni 50.8 Ti, Ni 51.0 Ti and Ni 51.5 Ti (atomic percent, %) pre-alloy powders were prepared by the electrode induction melting gas atomization technique, and the evolution of metallurgical defects, microstructure and mechanical properties of the three alloys were studied under different process parameters. The results show that the high Ni content NiTi alloy is prone to cracking perpendicular to the building direction during the LPBF forming process, and the formability is worse than that of the low Ni content NiTi alloy. The critical stress of the Ni 51.5 Ti alloy can reach 476 MPa at room temperature, but the fracture elongation is only 2%; the critical stress of the Ni 50.8 Ti alloy is only 122 MPa, and the fracture elongation can reach 8%.