Abstract: The processed satellite picture shows obviously a group of NW direction linear images in Tangshan seismic country, which reflect hidden faults that are noted for a large scale of left lateral slip movement and wrench faulting movement. The new activity of the faults affect respectively on topography, geological landforms and deep structure, also on the acttivity of recent tectonic movent. It is due to the evolution of regional tectonic movement. The NW direction hidden faults make us recoganize further the quake generating structure of the Tangshan earthquake (1979, 7, 28, M7. 8). The stress concentration on the intersection between NE and NW direction faults resulted in the earthquake finally.