Oil concentration is often used to ensure the grade of oil shale;however,other indexes,such as TOC and potential of hydrocarbon generation are used in evaluating oil and gas resource.It is very important to ravel the difference and the correlation among these indexes.In this paper,the connotations and the analysis process of several indexes are introduced.Moreover,15 samples of oil shale collected from Yanchang Group of Triassic,Ordos Basin,are used to conduct the analysis of these indexes.The comparison of these indexes shows that there is a linear positive correlation among oil concentration,TOC and potential of hydrocarbon generation;the oil concentration distributes in scope of 0%~12% with most in 3.5%~10% for the oil shale developed in Triassic,Ordos Basin;the oil shale belongs to normal or secondary grade and the oil shale with TOC>7% will reach the threshold(Oil concentration>3.5%) to render shale oil.