In the Tianjun region of the south Qilian basin,Marine carbonate has widely developed Middle Triassic calc-alkalic,which has a bigger thickness.According to the experiment and collect hydrocarbon source rocks data,we do some research in organic matter abundance,organic matter types and maturity of organic matter.In our opinion,the marine oil belongs to effective source beds.Organic matter abundance is high.And organic type belongs to Ⅱ2.Organic matter maturities of oil and gas have entered into the mature-high maturity period.Finally,we can conclude that the hydrocarbon source rocks of Tianjun region belongs to a middle grading considering of the effect of evolution function and weathering because the sample was collected from the ground surface.