Based on the distribution and compositions of various biomarkers in crude oils from the Niudong area and the Lenghu structure belt in the northern Qaidam Basin，this study proposed for the first time that crude oils from the Niudong area belong to typical coalderived oil. Those oils are characterized by higher Pr/Ph ratio (3.0～5.5) and plotted in the oxic zone in the diagram of Pr/nC17 and Ph/nC18, and rich in resinous compounds such as isopimarane and norpimarane, but relatively low C27 steranes related to algae input, suggesting that terrigenous organic matter has made an important contribution. In addition, neohopanes and rearranged hopanes are relatively low in those oils, which is consistent with coal and carboniferous mudstone. Therefore, these oils in the Niudong area should derive from coalbearing source rocks. As for crude oils from the Lenghu structure belt, their Pr/Ph ratios are relatively low (<3.0) and they are plotted in transitional zone between oxidation and reduction in the diagram of Pr/nC17 and Ph/nC18. The contents of isopimarane and norpimarane are obviously low, but C27 steranes related to algae input are relatively highter, showing that planktons are an important contribution, but resinite is significantly limited. Moreover, neohopanes and rearranged hopanes are moderate in those oils, consistent with fresh water lacustrine source rocks, suggesting that they are originally lacustrine oils.The correlation results from the relative abundances of isopimarane and norpimirane between the lithologically different J1 source rocks and the related oils in the study area show that the crude oils from the Niudong area are mainly derived from coals, not from carboniferous mudstones，and consistent with higher hydrocarbon potential of J1 coals in the study area. But the crude oils from the Lenghu structure belt were mainly generated by lacustrine mudstones. Therefore, much attention should be paid to coal derived oil exploration in the northern Qaidam basin.