The Altyn Tagh fault zone is an important strike-slip fault zone in northwestern China. The aeromagnetic data processed with methods of reduction to the pole and upward continuation offer plentiful information on faults and geological blocks. On such a basis, the geological-geophysical characteristics and displacement of main faults in the Altyn Tagh fault zone were analyzed. The detachment between its cap rock and basement was simulated by means of forward operation and inversion. Its formation time and tectonic evolution are discussed on the basis of geological data.