Abstract: Petroleum migration study of Bamianhe oilfield of Dongying depression, eastern China is observed on the basis of detailed work of investigating genetic mechanism and source rock of the petroleum. It is proved that pyrrolic nitrogen compound, a kind of non-hydrocarbon fraction, could be used as parameters in evaluating the quantity of migrated oil. Besides the pyrrolic nitrogen compounds, absolute quantitative analysis of aromatics such as dibenzofuran, dibenzothiophene and fluorene are also used for the evaluation. The results indicate that the pyrrolic nitrogen compounds and some heavy molecular compounds such as dibenzothiophene in the oils reveal significant fractionation effects. First, the main charging point of the Bamianhe fracture belt is at the location of the Xiaoqinghe River, where Mian 1 to Jiao 4 wells are located and also the oils migrated from the main charging point to the south and north respectively. Second, in the south part of the fracture belt, there are obvious migration fractionation effect laterally and vertically, suggesting most of the oil being accumulated at the south part. While the northern part of the fracture belt just shows slight oil migration fractionation effect from the main charging point to north. Third, at the end of the northern part of the fracture belt, the migration direction is seen to be from north to south, suggesting another source-cooker nearby. Fourth, according to the fractionation effect of the nitrogen compounds and aromatics, fractures and unconformity surfaces are inferred as the main migration paths, and the oils of the Bamianhe oilfield are assumed to come mainly from Niuzhuang and Guangli sags. It is also suggested that the oils are probably generated from the deep parts of the Niuzhuang and Guangli sags, not as what is suggested previously from the shallow sedimentary intervals in the south slope of Niuzhuang sag. Therefore, most of the oils are in fact normal oils generated by source rock in the oil-generating window.