Abstract: In this context,on the basis of comparison of three geochemical methods for assessment of source rocks,Rock-Eval pyrolysis,H/C ratio and hydrous pyrolysis,the hydrocarbon-generating potential of the low-mature coal in the Manjiaer sag,Tarim Basin,was determined.The compared results show that the potential of hydrocarbon-generating obtained by H/C ratio is similar with that by hydrous pyrolysis.The yields of hydrocarbon-generation based on the methods of H/C ratio and hydrous pyrolysis are 9.62 and 9.72 mg/g,respectively.In contrast,the yield of hydrocarbon formation is 32.75 mg/g by using method of Rock-Eval pyrolysis,higher than those obtained by the other two methods.It is provided the maximum yield of hydrocarbon generation for Rock-Eval pyrolysis,whereas the effective expelling of hydrocarbons will be obtained by H/C ratios and hydrous pyrolysis.Therefore,it would be necessary for hydrocarbon source assessment to use the geochemical method based on the special regions and aims.