According to the analytical datum of component carbon isotope and components and light hydrocarbon fingerprint natural gas, Sanzhan gas field genetic type and evolution degree of natural gas form research are think, natural gas are hybrid origin form humic-type and propelic-type organic matters. and is in over-mature evolution stage. According to gas geochemistry characteristic and source rocks distribution feature in Sanzhan gas fields, choose to source rocks specimens in Qingshankou Fm, Denglouku Fm,Yingcheng Fm, Shanhezi Fm and Hushiling Fm, five suits hydrocarbon source rocks is characterized by using the hydrocarbon fingerprint characteristic parameter of hydrocarbon source rocks, and the calculate model using mathematical simulation method. The ration contribution adjust per mouthful of well of natural gas from five suits of hydrocarbon source rocks to analog computation. Result makes known, per suit of hydrocarbon source rocks is contributed the disparity to the distinct well natural gas, Average contributions of deep layer in Shahezi Fm and middle-shallow layer in Qingshankou Fm hydrocarbon source rocks are 60. 5% and 9.9%. First obtaining natural gas ration source from Sanzhan gas fields.