Private finance includes all kinds of unregistered financial forms that are not controlled by the central bank. Generally speaking, private financing does not need formalities, and all the formalities are simple credentials, which simply write the borrower and lender, date, repayment amount or interest. Mortgage is a kind of legal guarantee behavior that takes the physical form owned by the mortgagor as the main body of mortgage and takes the form of not transferring ownership and use right as the debt guarantee. Therefore, it is wrong to say that mortgage loans belong to private financing.