Abstract: As one of the most important innovation mechanisms in the localization process of P2P, assignment of debt injects liquidity into the market,which is of great significance to the development of the industry. From the perspective of market liquidity, the paper collects 482 projects from “Hexindai” P2P platform, and uses propensity score matching and double difference model (PSM-DID) to study the effect of assignment of debt on P2P financing efficiency, including time cost and capital cost. The results show that the financing speed of P2P projects increased significantly, and the interest rate reduced significantly under the mode of assignment of debt, assignment of debt helps to alleviate investors′ investment bias; compared with short-term projects, the assignment of debt has a more significant impact on long-term projects, which have a disadvantage in terms of liquidity; compared with the production projects, the assignment of debt has a more significant impact on the consumer credit，which have a disadvantage in terms of information. In view of the positive role of the assignment of debt mechanism of P2P platform, the platform and the regulatory authorities should guide the independent innovation of the platform under the premise of controlling the risk to promote the standard growth and healthy development of the industry.

Key words: assignment of debt, liquidity, financing efficiency, P2P lending