Abstract: There are many arguments about the nature of mortgage right in legal studies.Mortgage right is a vouch right in the traditional theories of civil law.However,mortgage right,having some characteristics of debt right,is not typical of vouch right according to China's existing legislatures,because it has neither the ultimate dominance of ownership nor the real control of usufruct.In addition,mortgage right has neither the first compensated right nor the claim force of real right.It's difficult for us to classify the mortgage right according to the traditional classification standards of real right and debt right,because mortgage right has the dual nature of both real right and debt right.Classifying mortgage right into real right or debt right is to some extent based on legislature policies.