Abstract: A suit of thick grayish-black mudstone is intersected in the TD2 well in the southern boundary of Tuquan Basin. Spores and pollen fossils of 26 species in 19 genera, including Klausipollenites schaubergeri et al., which indicate an age of Late Permian, are found in the mudstone. Comparison of biostratigraphy and lithostratigraphy confirms that the strata belong to Upper Permian Linxi Formation. Analysis on the abundance, type and maturity of organic matter shows a great hydrocarbon-generating potential of the dark mudstone from TD2. The organic matter abundance is medium-good, belonging to Type Ⅱ₁, in overmature stage. This result suggests that the source rock of Linxi Formation in Tuquan Basin is promising for shale gas.