In view of the particularity and complexity of the subtle hydrocarbon reservoir in the west slope area of Qinan, the authors pointed out the difficulties in litho-reservoir exploration and provided the solutions according to the basic methods of the modern reservoir description. First, on the basis of improving resolution of seismic data, the strata were divided by utilizing sequence stratigraphy technique, and the object units of description were identified successfully.Second, the subtle structure features which existed in thin beds were detected accurately by applying several advanced techniques of structural interpretation, such as dominant band coherence processing and dip and azimuth angle composite detection that can identify small faults. Third, the spatial distribution regularities of bar sandbody of the 3rd Member of Shahejie Formation and special rock units of the 1st Member of Shahejie Formation were determined and the optimal litho-traps existing in different sequences in the west slope area of Qinan were delineated by various means such as drilling, logging, geological survey, oil test, integrating forward modeling(GMAPLUS), seismic inversion(JASON), classification(Stratimagic), Spec Decomp (LandMark), attribute analysis and optimization (MDI), true 3D interpretation, 3D visualization (GeoProbe) and pattern recognition. Finally, several pre-exploratory wells were arranged in the west slope area according to the results of comprehensive reservoir description in Qinan, and all of them later produced high-yield oil and gas. The series of detailed description technologies for subtle hydrocarbon reservoir produced in this study may provide a good example for other similar hydrocarbon reservoir exploration.