The formation energy, electronic structure, elastic and thermodynamic properties of close–packed hexagonal Ni3Ti intermetallics doped with alkaline earth metals (Be, Mg, Ca, Sr, Ba) have been calculated by first principles method. The influences of pressure and strain on elastic properties are also investigated. It shows that the alkali earth metals tend to occupy the Ti sites preferentially. The formation energy of the doping system increases gradually with the doping concentration increase. The calculated electronic properties indicate the pseudo–energy gap of the system narrows down when the doping atomic radius increases, indicating the proportion of covalent bond decreases gradually with atomic radius increase, resulting in the elastic strength weakened and the ductility enhanced. The Debye temperature and thermal conductivity also decrease with atomic radius increase. The elastic property of Ni12Ti4-xMx (M = Be, Mg, Ca, Ba) is sensitive to strain index except Ni12Ti4-xSrx while the applied strain restrains the elastic anisotropy to some extent.