legal ground
Article 34 of the Measures for the Administration of Urban Real Estate Mortgage
If the real estate obtained in accordance with the law is mortgaged, the registration authority shall record his rights in the original house ownership certificate, and the mortgagor shall accept it. And issue the real estate license to the mortgagor. If the pre-sale of commercial housing or the construction in progress is mortgaged, the registration authority shall record it in the mortgage contract. If the mortgaged real estate is completed during the mortgage period, after the mortgagor obtains the certificate of real estate ownership, the parties concerned shall re-register the real estate mortgage.