The Hongche fault belt-Chepaizi uplift in the northwestern margin of Junggar basin has many oil and gas reservoirs. As the physical and chemical properties and geochemical characteristics of crude oil are very complex, the type and source of crude oil have long been controversial, which directly affects decisions on oil and gas exploration. Based on the summary of typical geochemical characteristics of crude oils and main oil source identification indexes in different ages of Junggar basin, this paper systematically analyzed and studied the geochemical characteristics and sources of the crude oils in the Hongche fault belt and the Chepaizi uplift, and divided the crude oils in this area into three types with single source and two types with mixed sources. Three types of single source crude oils were derived from the lacustrine source rocks of the Permian, coal measure source rocks of the Middle and Lower Jurassic, lacustrine source rocks of the Paleogene Anjihaihe, respectively. The two types of mixed crude oils were mixed from the biodegraded heavy oil derived from the Permian lacustrine source rocks, the normal crude oil derived from the Middle and Lower Jurassic coal measure source rocks, and the normal crude oil derived from the Paleogene lacustrine source rocks. The crude oil of the Carboniferous-Cretaceous oil reservoirs in the Hongche fault belt was mainly derived from the Permian lacustrine source rock, and the heavy oil in Chunfeng oilfield in the northeast of Chepaizi uplift was also derived from the Permian lacustrine source rock. Light crude oil in the Neogene Shawan Formation oil reservoir on the east side of Chepaizi uplift and west side of Hongche fault belt was derived from Paleogene lacustrine source rocks. The heavy oil of the Cretaceous-Paleogene oil reservoirs in the Chunguang oilfield in the middle of Chepaizi uplift is amixture of the Permian sourced heavy oil and the Jurassic sourced normal crude oil, and the heavy oil of Neogene Shawan Formation oil reservoir is amixture of the Permian sourced heavy oil and the Neogene sourced normal crude oil. The light crude oil of the Carboniferous-Paleogene oil reservoir in the west of Chepaizi uplift was derived from the Middle-Lower Jurassic coal measure source rocks, while the light crude oil of the Neogene Shawan Formation oil reservoir was derived from the Paleogene lacustrine source rocks. This paper has important implications for the study of hydrocarbon accumulation and regional oil and gas exploration and decision making in the southern area of northwest margin of Junggar basin.