Abstract: The securities margin trading guarantee system is an important part of financial legal infrastructure. The accurate description of the securities margin trading guarantee from the perspective of private law can help to clarify the boundary of rights and obligations of the parties, and provides the basis of claim in private law enforcement, so as to reduce the regulatory burden of public law enforcement. The present academic analysis has not determined the legal constitution of the securities margin trading guarantee. The Civil Code has introduced the functionalist guarantee concept, by which the transferring guarantee obtains the legitimacy recognition in the way of atypical guarantee, thus substantial applicable evidences are provided for the legal constitution of the securities margin trading guarantee. In terms of interpretation, the transferring guarantee can establish the account system of the securities margin trading guarantee, the scope of collateral and other specifications, but the absence of registration rules will affect the effectiveness of the forced liquidation. In terms of laws and policies, in order to meet the requirements of unified guarantee registration by the Civil Code, legislators should stipulate that the party registered in securities margin trading has the prefer efficiency, so as to promote the connection between the legal theory and the business practice.

Key words: securities margin trading guarantee, trust structure, maximum pledge right, transferring guarantee, forced liquidation