Abstract: Based on plenty of systematic analytical and experimental data and geochemical characteristics of petroleum exploration in the northwest Tarim Basin, the paper mainly approaches the compositions, light hydrocarbons, and carbon isotopic characteristics of the natural gas, as well as the divisions of the origin types in the area. The study reveals that the northern Tarim Basin is dominated by oil-prone gas with minor coal-prone gas and mixed gas. However,the Yakela uptaulted area is mainly predominated by gas-conden-sate gas, while in the Akekule embossed area, it prevails pyrolytic gas. Only minor helium gas is produced at the Shaxi uplifting area.