Large-scale thrust system was discovered in North Lhasa Block, which is called the North Lhasa Thrust (NLT). It consists of the Nam Co tectonic belt as the front part, the Ando-Lunpola tectonic belt as the root part and the detachment layer at 15 - 30 km depth within the middle-upper crust as the lower part. The Nam Co tectonic belt of WNW-trending occurring in west of the Namco Lake is composed of 20 thrust faults of north dipping, wide ductile shear zone, 4 belts of ophiolite pieces and many thrusted rock pieces. The Ando-Lunpola tectonic belt located in middle of the Bangoin-Nujiang suture includes 3 thrust faults of WNW-trending, wide ophiolite complex and folded basins of the Early Tertiary. The lower part of the NLT, the detachment layer in middle-upper crust, is corresponding to the high-conductivity layer of crust at depth of 15 - 30 km and is comprised of ophiolite pieces and thrusted rock pieces. The southward thrusting of the NLT is about 120 -150 km, which mainly occurred in late Oligocene-early Miocene.