Most of information about the source rocks was commonly taken from the analysis data of Mesozoic strata outcrops but hardly any from Paleozoic strata in Qiangtang Basin in the past because of virgin exploration. Analysis samples are from a group of drilled cores of Permian Zhanjin source rock from Wel Qiangzi-5 that was solely dril ed in the plateau basin recently. The result of organic geochemical analysis shows that Zhanjin source rock belongs to the rank“good”for high TOC values (the average 1.15,) and good kerogen types of dominant Type- Ⅲ and seldom Type- Ⅱ2. Organic matter general y derived from marine low-grade aquatic organism and thermal y evolved into mature stage, which means good gas-generating capacity of the source rocks. The core samples from the well have demonstrated organic matter being mature;but even so, affected on late tec-tonic uplifting, the unknown Permian source rocks that are deeply buried probably are high mature or over mature. It is implied that the deeply-buried Permian source rocks are of good prospective for oil and gas exploration in the basin.