通过分析天然气组分与甲烷碳同位素特征发现，河套盆地第三系上新统—第四系更新统确有生物气存在。详细的有机地球化学资料分析表明，河套盆地第四系更新统中、上段气源岩的有机质含量丰富，干酪根类型以Ⅱ₂、Ⅲ型为主，母质来源表现出高等植物为主，低等水生生物混入的特点，有机质演化处于生化甲烷阶段，非常利于生物气的形成。在建立生物气生成演化模式的基础上，根据区域地质条件，提出河套盆地生物气生成的最佳深度范围为685～926 m，位于第四系更新统中段。

The analysis of natural gas composition and carbon isotopes of methane confirms the existence of biogenic gas around the Tertiary Pliocene series and the Quaternary Pleistocene series in the Hetao basin. Detailed organic geochemistrcal data shows that the biogenic gas source rock of the middle and upper Pleistocene series in this area contains a high content of organic matters and typesⅡ₂ and Ⅲ kerogens. The organic matter in the biogenic gas source rock is in low-mature stage, which is benefit for the formation of biogas. In addition, this article establishes a generation-evolution model of biogas, taking into account the region geology feature and temperature affection on the biogas generation, and puts forward that the best vertical extent for biogenic gas formation in the Hetao basin is in the middle of the Quaternary Pleistocene series, between 685 meters and 926 meters.