The Great Counter Thrust (GCT) in the northern margin of the Himalayan orogen belt is located in the boundary of India-Asia collision and is also parallel to the Yarlung Tsangpo suture zone (YTSZ). Northward thrusting of the GCT resulted in the superimposition of the Tethys-Himalaya over the Gandese magmatic belt. The GCT constrains the development of the Miocene Kailas-type molass basin (including Kailas, Qiuwu, Dazhuqu, Luobusha and Langxian), with molass deformation gradually increasing from west to east. This study carried out the geochrological analysis of the conglomerate from the east section of the GCT. The results show that sedimentary age of detrial zircon from the Luobusha-Langxian conglomerate is early Oligocene (28.7~29.1 Ma). The pseudotachylyte, metamorphosed and mylonitic conglomerates are extremely well-developed in the Luobusha-Langxian formation. The Luobusha-Langxian conglomerate is characterized by matrix mylonitization, pseudotachylyte and northward shearing, suggesting that the molass basin controlled by the GCT faulting has experienced three stages of tectonic evolution, (1) formed at shallow depths, (2) underthrusted into depths about 10~15 km and with the pseudotachylyte formation, (3) exhumed into surface.