In Baigang ophiolitic mélange of the Yarlung Zangbo Suture Zone exposes an unusual spinel-garnet lherzolite block, which is surrounded by soft crust of serpentinized lherzolite. In this block, there are four kinds of clino pyroxene. They are earliest recrystallized matrix clino pyroxene, exsolution clino pyroxene, inserting clino pyroxene, and exotic clastic clino pyroxene. It can also be seen the metamorphic reaction that is calcarous pyroxene + spinelandradite. We also find there are some needle like humite exsolution in olivine in both core and crustal lherzolites. Geo thermobarometers are applied to these lherzolites, which give a result of higher than 900℃ temperature and more than 1.8GPa pressure, and also implies that the spinel-garnet lherzolite block have experienced a letter N like tectonic route composed of ascending, subdction and re-ascending three stages.