Abstract: There are three different types of crude oil in reservoirs of Pinghu oilfield. The oil can be discriminated by obvious geochemical parameters with carbon isotope of aromatic hydrocarbon as the fingerprint marker. The oil was migrated from southwest to northeast and from reservoir H₆ in the lower part to reservoir H₂ in the top. And hydrocarbon migration was controlled by structural uplift. The reservoirs were well connected, although the light deasphalted action of oil blocked some pores of reservoirs.