Normal style="MARGIN: 0cm 0cm 0pt">Based on the analysis of the precise biomarker characteristics, type classifications and comparison of crude oil and source rocks, the effective source rocks of Yanchang formation in southern Erdos Basin were considered to be oil shale and mudstone in Chang 7. The identification mark of biomarker-normal geochemical evaluation-log electrical parameters in Yanchang formation of upper Triassic in southern Erdos Basin was established according to the geochemical characteristics and logging characteristics. The parameters are as follows : 8 β (H) -homodrimane/8 β (H) -drimanes 〈2, w (TOC) 〉 1.6%, S1 +S2 〉4 mg/g, IH〉170 mg/g, GR〉120 API, △t〉260μs/m,RT〉15Ω•m, CNL〉27%. Logging calculation formula of w (TOC) and IH was established according to the correlation of geochemical parameters and electrical ones, which has realized the cohesion of geochemical information of limited core to the whole interval logging information.