Abstract: Turpan-Hami basin is a composite petroliferous basin developed under multiple periods of tectonicmovement with multiple series of hydrocarbon source roeks including Permian,Triassic and _Jurassic. The periods ofearly,middle-late Yanshan movement and Himalayan movement are its major periods for hydrocarbon generation andexpelling. By influence of multi-period structural movements,not only are “coal-type”and “oil-type”pools with singleorigin found, but“source-mixed-type”pools existed,, and the higher degree of exploration, the more of the pools arefound. This paper analyzed the formation mechanism and geochemical features of this type of reservoir,and discussedthe method for using crude carbon isotope quantitative analysis to determine the mixed ratio. It is indicated that thismethod is feasible, thus making the mixed ratio problem arisen in the basin be solved finally.