Mortgage means that the mortgagor and the creditor conclude an agreement in writing not to transfer the possession of the mortgaged property, and take the property as the guarantee of the creditor's rights. When the debtor fails to perform the debt, the creditor has the right to discount it according to law or give priority to compensation with the price of auction or sale of the property. In theory, private lending also needs collateral. Bank loan refers to an economic behavior that banks lend funds to people in need of funds at a certain interest rate according to national policies and return them within the agreed time limit. Bank loans generally need to provide guarantees, house mortgages, income certificates and good personal credit information before they can apply. In different countries and different development periods of a country, the types of loans classified according to various standards are also different.