Abstract: The obligation law system includes internal system and external system. Values such as human rights, human dignity, freedom, order, equality, integrity, fairness, effi ciency, autonomy of the will and other values, as well as the specifi c values of obligation law, such as encouraging trading, ensuring trading safety and demarcating the boundary between freedom of conduct and the willingness to help others, are not contained in the norms of civil law in a disorderly way, but each has its own functions and links with each other. There is a hierarchy relationship between some values, which constitutes the internal system of obligation law. It is inevitable and necessary to be externalized into the external system of obligation law. According to the Pandekten model, obligation and obligation law as the supreme concept include the obligation founded on contract, fault in negotiation, a single act, negotiorum gestio and unjust enrichment. Extract these types of "common factors" to form the general provisions of the law of obligations. Although the Civil Code of the People's Republic of China is not completely designed in this way in form, it is necessary to integrate all related, fragmentary rules of obligation law into a systematic framework according to the Pandekten model. 

Keywords: Obligation Law; System; Internal System; External System; Type of Obligation; Pandekten