Direct manufacturing of metal parts by selective laser melting (SLM) is a newly rapid prototyping technology. Metal parts with metallurgical bonding, high density approximately 100%, low surface roughness and high dimensional accuracy can be produced by SLM in one step. Selective laser melting of Ti-Ni alloy which has excellent biocompatibility is potential for the fabrication of implants and prostheses. The effects of processing parameters on build up characteristic, surface quality and densification such as laser power, scan speed were studied. Gradient grid structure, mechanism and elimination methods of warping of metal parts are analyzed. Experiment result shows that special scanning strategy can reduce the difference in temperature and eliminate warping. The microstructure analysis result shows that a complete metallurgical bonding is obtained by selective laser melting process, and arborescent crystal and isometric crystal were investigated. The microstructure distribution depends on process parameters such as scan strategies, scan speed and laser power.