The density of liquid Ni-Ti alloys were measured by electrostatic levitation technique and the maximum reduced undercooling of triangle T/T-L reaches 0.23. Quite different from the linear relationship between density and temperature for liquid Ni45Ti55 and Ni55Ti45 alloys, the density of liquid Ni50Ti50 alloy displays a nonlinear dependence on temperature. Interestingly, the density increasing tendency of liquid Ni50Ti50 alloy rises more rapidly with the decrease of temperature, which results from the more severe shrinking of the distance among atoms at lower temperatures. In addition, the thermal expansion coefficient of liquid Ni50Ti50 alloy increases linearly with the decrease of temperature. (C) 2017 Elsevier B.V. All rights reserved.