In order to find out the gas source of gas hydrate in Muli coal field, Qilian Mountain permafrost, geochemical characteristics of Triassic source rocks are studied. According to the depth, 36Triassic samples of JN well were collected. First, for analysis of the maturity and hydrocarbon potential, the normal geochemical experiments, for example, rock pyrolysis and analysis of organic carbon were completed. Then 9 samples were selected to carry out the microscopical maceral identification of organic petrology test. Finally, 4 samples were studied by Soxhlet extraction and GC-MS test. The results showed that research region Triassic source rocks mostly are in high maturity stage; Organic matters mainly belong to Ⅱ-Ⅲ type, which are mainly from higher plants and lower aquatic organisms mixed sources; the sedimentary environment is the epicontinental sea and shore-delta; Organic matter abundance is in relatively high, belonging to mid-good source rocks.