Titanium dioxide nanoparticles are white loose powder with superior ultraviolet-shielding effect, dispersibility and weather resistance. They are often applied as a novel nano-material in the production of cosmetics, functional fibers, plastics, coatings and paints, and may therefore enter the human body through the respiratory tract, digestive tract or skin contact. In recent years, with the extended application of titanium dioxide nanoparticles in various industries, the safety and potential harm of titanium dioxide nanoparticles have attracted great attentions. This article evaluates the safety of titanium dioxide nanoparticles from the perspective of physicochemical properties, exposure pathways and the mechanisms of neurotoxicity based on currently available studies. In addition, the research progress and the prospects of titanium dioxide nanoparticles are discussed.