Porous TiNi intermetallic compounds have a promising future as biomaterials, with some challenges for their corrosion resistance. In this work, TiNi intermetallic compound was prepared by reactive synthesis of elemental powders. The evolution of the microstructure and phase composition of TiNi at different temperatures was studied. And the electrochemical corrosion behavior of TiNi intermetallic compound in NaCl solution was investigated by electrochemical tests. The results show the formation of a core-shell structure during the sintering process, where Ni is the core and Ti2Ni, TiNi and TiNi3 are the shells. With uniform diffusion, a large pore replaces the Ni core due to the Kirkendall effect. TiNi intermetallic compound has a well-developed open pore structure with an open pore ratio of 50.98%. TiNi intermetallic compound exhibits better corrosion resistance compared to Ni and Ti, which can be attributed to the generation of passivation film on the surface.