Abstract: A number of Cenozoic terrestrial basins with varying scales are located on the Bangong-Nujiang suture in Central Tibet.These basins are characterized by high TOC,high quality sedimentary organic matter and moderate thermal maturity which have well oil and gas exploration foreground.The authors have focused on the section from Upper Niubao Member in Awengcuo basin and studied the organic matter abundance,organic matter type and organic matter maturity of the hydrocarbon source rocks.The results have shown that the average organic carbon contents of the limestone(marlite and micrite) are 0.53%,and 0.95% after recovered which means that high quality hydrocarbon source rocks have developed in Upper Niubao Member.The type of organic matter of limestone is mostly Ⅰ and Ⅱ₁.The maturity of organic matter in Upper Niubao Member is not high,representing almost in the stage of low maturity.The general evaluation of source rocks is medium in Upper Niubao Member of Awengcuo basin.