Eastern Niger Basin is a typical Mesozoic-Cenozoic intracontinental rift basin of the Central-Western African rift system. The Tenere Depression, located in the northwestern part of the basin, includes the Western Sag, EasternⅠSag and EasternⅡSag. Analysis of mudstone cuttings from Well Saha-1 has revealed that kerogen macerals are dominated by amorphinite without or with weak fluorescence andC29 regular sterane are predominant in rock extracts. On these characteristics, it is suggested that the organic matter of the Upper Cretaceous mudstones mainly derived from terrigenous plants. Rock-Eval pyrolysis data reveals that the Upper Cretaceous Yogou mudstone generally is moderate to good hydrocarbon source rock with predominant TypeⅡ2 to TypeⅢ of kerogen while the Donga mudstone is mainly poor to moderate source rocks with TypeⅢ of kerogen. The max values indicate that the depth of hydrocarbon-generating threshold is about 2300 m. Thermal-burial history modeling implies that of Yogou mudstone (Well Saha-1) is not mature. Donga mudstone has reached the oil-generating threshold at the end of Cretaceous and the lower part of Donga is in gas-generating stage. By integrated study, it is suggested that better potential for hydrocarbon exploration exists in Western Sag compared with that in the EasternⅠSag and EasternⅡSag.