Abstract：The tectonic stability of the Tamusu region is crucial for its pre- selection as a high- level radioactive waste disposal site, and comprehensive system investigations and safety assessments are required. Combined with field geological data, Mineral composition and iron species of fault gouges and its wall rocks in three fault zones of Tamsu area had been analyzed by the X- ray diffraction and the Mossbauer spectroscopy. The results showed that，①the fault gouge and its wall rock of Tamusu fault(F2) mainly consist of quartz and feldspar, the fault gouge contains a small amount of clay minerals and the wall rocks contain almost no clay minerals, the fault gouge and its wall rock only contain para- Fe3+ and mag- Fe3+；②The fault gouge and its wall rock of Wulantiebuke fault(F4) are dominated by clay minerals and calcite with trace amounts of pyrite, the clay minerals are mainly illite, smectite and illite mixed layer, the iron species of wall rock only contain para- Fe2+ and pyr- Fe 2+, whereas the fault gouge contains a small amount of para- Fe3+；③Except the TMS04 do not contain calcite, he fault gouges and its wall rocks of Narenhala fault(F7) consist of quartz, feldspar, clay minerals and a small amount of calcite. Clay minerals are mainly composed of chlorite, illite and smectite. The fault gouges and wall rocks only detected the para- Fe2+ and para- Fe3+. The para- Fe3+ in TMS04 was higher than that of para- Fe2+, and the para- Fe2+ in all samples was slightly higher than that of para- Fe3+. The mineral composition and iron species distribution of fault gouges and wall rocks were closely related to the evolution of faults, and their differences showed that the complex connectivity relationships between the faults and the deep and the outside world in the Tamusu region, and the faults are in a relatively stable state.