Abstract: The Beipiao Formation, an important series of coal measure in western Liaoning Province, is considered as a key target for oil-gas exploration, within which two typical sections namely Kuntouyingzi and Wolong are of great significance to study the sedimentary environment and organic matter sources. With analytical tests on the source rock samples from both sections by GC-MS technique, the results indicate that two groups of samples show different geochemical characteristics as follows. The samples from Kuntouyingzi section show unimodal patterns in the n-alkane distribution with dominant peak of C₁₉ and Pr/Ph of 3.0-4.0. Regular steranes are dominated by C₂₉-sterane, indicating higher plants. The terpene is characterized by low content of C₂₃ tricyclic terpene and tetracyclic terpene with low gammacerane value (averagely 0.08). For the samples from Wolong section, the n-alkane is distributed in bimodal pattern with C₁₈ as dominant peak and low Pr/Ph ratio (less than 0.4). The regular steranes are dominated by C₂₇-steranes. The terpenes feature high content of C₂₃ tricyclic terpene with a relatively high gammacerane value (averagely 0.23), and all the maturity parameters have reached the heterogeneous equilibrium stage. Combined with the whole rock maceral analysis results, it is thought that the main differences between the two may be caused by igneous intrusions near the sections. The organic matters are mainly derived from terrigenous higher plants plus a few lower aquatic organisms such as algae and bacteria.