The Muli Coalfield, located in the northeastern part of Tibetan Plateau, was recently discovered to host gas hydrate in the Jurassic Yaojie Formation in the Juhugeng Mining area. In order to obtain understanding of gas type and sources of gas hydrate, this study carried out detailed research on organic matter abundance, organic matter type, vitrinite reflectance, alkane carbon isotopic characteristics of source rock samples from the Middle Jurassic Yaojie Formation of the Juhugeng coal mine area. On the basis of the result above, we studied the similarity and difference of alkane gas in gas hydrate and coalbed gas and finally determined the genetic type and source of gas hydrate in the study area. The results show that ① the hydrocarbon source rocks of the Jurassic are abundant in high organic matter abundance, and belong to good source rock. The organic matter type belongs to the type I kerogen, with vitrinite reflectance of 0.65%~1.32%, and thermal evolution degree reaching the petroleum gas phase. ② Carbon isotopic characteristics show that the majority of alkane belongs to positive carbon isotope series, and the values of δ13C2 are less than -28 ‰, belonging to petroliferous gases. Alkane carbon isotope series of DK2 drilling at the depth of 141.5m is reversed, indicating the gas is a mixture of the coal gas and petroliferous gases. ③ Carbon isotope characteristics of hydrocarbon from source rocks in Jurassic and gas hydrate are highly consistent, suggesting that the gas source of natural gas hydrate derived mainly from lacustrine mudstone and oil shale of the Middle Jurassic Yaojie Formation.