In recent years，under the background of Financial Supply-side Structure Reform and real estate market restriction，China is learning from the experiences of overseas real estate financial market and conducting in-depth exploration on the REITs system. Based on the domestic existing legal system，China’s “Quasi-REITs” is introduced to the Real Estate Financial Market. According to the characteristics of Basic Assets，“Quasi-REITs” can be divided into Repurchase-Quasi-REITs and Equity-Quasi-REITs. This paper tries to find out the legal basis of Repurchase-Quasi-REITs from the perspective of Alienation Guarantee System. Firstly，the paper analyzes the Basic Asset Construction process of Repurchase-Quasi-REITs based on practical experience，as well as the characteristics of the “Equity and Debt Structure” and “Pre-emptive Right” in Repurchase-Quasi-REITs. Secondly，this paper introduces the Alienation Guarantee System and explains the legal nature of Repurchase-Quasi-REITs from the perspective of Alienation Guarantee in a broad sense. Finally，this paper further investigates the legal nature，and effectiveness of the “Pre-emptive Right” in Repurchase-Quasi-REITs in order to provide beneficial reference for the Business activities and judicial practice.