In the previous analyses, the genitive case was treated as homonym in traditional grammar and much effort was concentrated on structural analyses of it disregarding meaning in transformational grammar. Therefore both analyses didn`t capture the generalization of genitive case. In the present analysis, many uses of genitive case are scrutinized in both horizontal and vertical axis, that is, extension and elaboration on the basis of cognitive grammar, especially prototype theory of categorization and one principle ruling genitive case is suggested. I call it "Power dominance principle". Power dominance is realized as possession, origin, part-whole, kinship, belonging, apposition, relation, cause, measure, etc, in contexts.