Using first-principles pseudo-potential plane wave method

the formation enthalpy

cohesive energy

density of states and electric density of difference were calculated and analyzed for NiTi（B）and NiTi（Nb

B）phase after boron elements adulterating process.The results show that in NiTi basic crystal

boron atom has much more formation ability in 4Ti2Ni octahedron structure than that in 4Ni2Ti. However

in NiTi（Nb）solid solution crystal

the nearest neighbor site of B-Nb is more stable than the next nearest neighbor site

and the formation ability of the former impurity site is stronger than the next one.The simulation of density of states and electronic density difference shows boron preferring to bonding with Ti atoms and Nb atom

while the bond strength of B-Ni is weak.Such bonding process results in the action of Ti atoms decreasing and the ratio of Ni/Ti increasing

deteriorating the properties of NiTiNb alloy by boron impurity.