Abstract: The theoretical system of the civil law in China is“transplanted”from the continental law system and is established mainly by inheriting or accepting the theory of civil law of Germany and Taiwan Province of China. There is no provision on the system of paying debts with property in Chinese current law, but there are a large number of cases of paying debts with property in judicial practice. Due to the inherent defects and deficiencies of the system of datio in solutum in the traditional civil law, and the abuse between paying debts with property and datio in solutum, the judgment rules of the above cases are relatively in chaos and seriously affect the judicial justice. Therefore, it is urgent to further clarify it in theory. In essence, the act of paying debts with goods is a consensual contract of liquidation, the solvency is the main difference between it and the novation of obligation object. Its extension can cover such concept categories as the traditional datio in solutum, the appointment of datio in solutum and new debt paying-of, which belong to the type of receiving other payment in reality, thus it is more open and inclusive.

Key words: paying-a-debt-in-kind, datio in solutum, real contracts, consensual contracts, voluntary obligation