Base on the embedded-atom method，the enthalpy and the density of Ni2TiAl alloy are calculated by using molecular dynamics simulations.The temperature dependence of the specific heat of normal and undercooled liquid Ni2TiAl alloy is obtained.The results indicate that the specific heat and the density increase linearly with the decrease of temperature，and the Neumann-Kopp rule can be applied to estimate the specific heat of undercooled liquid Ni2TiAl alloy. Meanwhile, the size effect in the simulation domain is indicated to be negligible.