Abstract: According to analyses data of source rock samples from surface and underground,it is described in this paper distribution,geochemical characteristics and influential factors of Carboniferous source rocks in the Bayehot Basin.2 types of source rocks are generated in the basin: dark mudstone and limestone,mainly locating in the Chouniugou,Jingyuan and Yanghugou Formations of the Middle-Lower Carboniferous.Dark mudstone works as good source rock,with middle-good organic abundance,sapropel-humic and humic organic types as well as mature-high mature generation stage.Carbonate with lower organic abundance can generate certain hydrocarbon,yet has poor generation potential with less thickness and limited distribution.Sedimentary environment and tectonic movement have great influence on abundance and thermal evolution extent of organic matters.The most favorable source area of Bayehot Basin distribute in the sedimentary area of littoral-neritic delta and near-shore shallow sea facies trending NE to the north of Wuda-Bacan2-Xi1-Chahabuleg.