The paper deals with the sequence and lithological characteristics of the Lower Permian Pangduo Group in Linzhou county, northern Lhasa, Tibet and discusses its origin. The sequence of the Pangduo Group was not clear and the origin of the diamictite was disputed previously. Based on investigation of more than 7 sections, the sequence of the middle and upper part of the Pangduo Group was established along the road between Pangduo and Dangxiong. Sandy conglomerate and wavy laminated sandstone with dropstones of the slope facies affected by glacier is characteristic of the upper part of the Lower Pangduo Group. The middle of the Pangduo Group is characterized by well-developed boulder-bearing shales or pebbly slates interbedded with turbidite. This indicates a basin facies affected by glacier. Well-developed sandy conglomerate and shallow water sandstone interbedded with pebbly mudstone or pebbly sandstone features the upper part of the Pangduo Group. This indicates the shallow water facies to slope facies influenced by glacier. The whole characteristics of the Pangduo Group suggest a glacio-marine environment.In the lower part of the middle Pangduo Group, a layer of basalt was found, and it indicates that the middle part of the Pangduo Group was deposited in a tectonic background of rift. The series of the middle and upper Pangduo Group shows the course of the filling of the rift. Another period of tectonic movement after the deposition of the Pangduo Group is presumed based on the high content of feldspar and volcanic debris in the rock and the existence of tuff in the overlying Wululong Formation (P_2w). Suspected altered granite or rhyolite was found between the Pangduo Group and Wululong Formation (P_2w).Based on the finding of glaciogene pebbly slates in the middle Pangduo Group and the analysis of the characteristics of the diamictite from the Pangduo Group, we suggest separating underwater tillites from turbidite. The differences between them were discussed and the appearances of the two kinds of rocks were showed in the paper.