Fundamental legal concepts can be identified empirically,but they need to be justified logically.The formal deduction of fundamental legal concepts can be achieved by the integration of Hohfeld\'s theory and logical method.Fundamental legal concepts should be defined and expressed as follows:right,duty,no-right,no-duty,power,liability and no-power,no-liability,and their relations should be specified as relations of external negation,correlation and classification.The substantive construction of fundamental legal concepts needs to fill the gaps in Hohfeld\'s theory and ground fundamental legal concepts in certain legal thought.Given the mutually interpretive relations between legal thought and particular types of legal norms,as carriers of concepts in the “right” and “power” groups,legal norms can be classified as two types related to legal thought.The theory of the object of right,and especially the fact that the right therein can become the object of right,lays a foundation for interpreting the relation between right and power.In structural terms,right and power have a nested relation;in terms of properties,their relation is one of contradiction;functionally,it is one of means and end;in terms of amounts,it is one of equivalence;and in terms of logic,it is one of mutual priority.As the fulcrum of fundamental legal concepts,the dual structure of right-power has not only inspired theories relating to the types and nature of right but also provided modern jurisprudence with an interpretation of two-order construction of the concepts of law,the legal system and legal order.Its theory of practice rests on the fact that it offers a micro-mechanism shared by all forms of governance.