In Hegel′s Criticism of Legalist Philosophy and its Introduction, Marx criticizes the ontological basis of Hegel′s speculative idealism theory of the state built on Feuerbach′s humanism materialism. It is asserted that existence comes from existence itself and thinking stems from sensual existence. Thus, thinking is interpreted by sensual existence and political state and the spirit are accounted for by realistic sensual existence to understand the relationship between civil society and political state. Then, in introduction, Marx not only insists on such existence theory and methodology, but also combines Feuerbach′s humanism materialism philosophy with proletariat theory in revolutionary practice to reform unreasonable social relationship in reality. In general, Marx criticizes Hegel′s theory of the state at perceptual experience level and lacks philosophical reflection on reality. Therefore, Marx is unable to deeply understand the realistic connotation of Hegel′s idea on regarding the state as the self-realization of the state. However, regardless of the success or fallings of Hegel′s Criticism of Legalist Philosophy and its Introduction, it promotes the development of Marx′s theory changing from historical theory to historical materialism.