The author comparatively analyzed and compared some present important indicators (vit rinite reflectance ,reflectance of solid bitumen ,reflectance of vit rinite2like maceral ,reflectance of organic f ragment such as graptolite ,chitinozoan and scolecodont ,color index alteration of conodont , etc. ) with reference to the degree of maturation of marince hydrocarbon2source rocks ;on the basis of sum up their advantage and disadvantage ,the author suggested the principle of selection to the organic maturation indicator of marine hydrocarbon2source rocks ;still further ,the relative fluorescence intensity ( I546) is suggested and regarded as a good indicator of determining the degree of maturation of marine hydrocarbon2source rocks in this paper. The relative fluorescence intensity is well suitable to determine the degree of maturation of marine hydrocarbon2source rocks lack of vit rinite.