Abstract:The distribution of high quality source rocks is one of the important factors which controls the distribution of oil and gas in rift basins,with its accurate identification ,we can provide the advantageous basis for the next step of oil-gas exploration. This paper adopts the rich logging data , using an improved ΔlogR model, to identify high-quality source rocks in Wuerxun and Beier Depression, and predict its distribution. It is proved that improved model is simple objective and more accurate in quantification as the result shows in Wuerxun and Beier Depression. The correlation coefficient R is high between Calculation organic carbon and Measured organic carbon.In Wuerxun depression high quality source rocks are mainly distributed in southern and northern part ,in Beier Depression mainly distributed in Central Western and Southwest three parts.