Abstract: It was believed from previous studies that the Upper Devonian in Madre de Dios basin was the“world class”source rocks. This paper compares the source rocks from Upper Devonian Cabanillas group (Peru) and Tomachi formation (Bolivia) in differences of the type and the abundance of organic matter and the hydrocarbon potentials, and proves that the two are not the same set of source rocks. According to sequence stratigraphy analysis, it is believed that Cabanillas group is overlying the Tomachi formation. Therefore, the Upper Devonian in Madre de Dios basin is not a world?class source rocks. Meanwhile, based on the geochemical characteristics of Cabanillas group and geological analysis, the Cabanillas source rocks mainly generate gas. The main resource type of this basin is gas, and the benefit for exploration of it will be lower