In this paper, The nuclear magnetic resistance study of evaporated Ni / Al + tox O 2 / Ni thin films is investigated duo to the potential application in industry because of their tunneling magnetoresistive characteristics. Results showed that the nuclear magnetic resistance of this metal-insulator-metal thin film structure is useful in determining several important fabrication parameters, such as the Ni crystal structure and the optimal O 2 plasma oxidation time ox of the Al spacer layer.