1. Prepare relevant documents: the owner holding the certificate of immovable property should find the certificate of immovable property so as to check the detailed information on the certificate.
2. Bank inquiry: You can contact the bank holding the certificate of immovable property, provide them with the certificate number or other necessary information, and ask whether there is mortgage registration.
3. Inquire about the provident fund center: If you suspect that the mortgage is in the provident fund center, you can contact the local provident fund center to provide relevant supporting materials and ask if there is mortgage registration.
4. Inquire about the real estate register: In China, the real estate register is a legal document that keeps all real estate mortgage and transfer information. You can query the real estate register through the real estate registration agency to obtain mortgage information.
Please note that the above method is only a preliminary inquiry. If you need exact information, it is best to consult a professional real estate lawyer or consulting agency, who can help you learn more about the mortgage of real estate license.