If the parties signing the agreement have civil capacity, the agreement was signed voluntarily by the three parties, and the content of the agreement does not violate the mandatory provisions of laws and administrative regulations, and does not violate public order and good customs, the agreement shall be legally binding. Legal basis: Article 36 of the "Urban Real Estate Management Law of the People's Republic of China" For the transfer and mortgage of real estate, the parties concerned shall handle ownership registration in accordance with the provisions of Chapter 5 of this Law. Article 62 When mortgaging real estate, mortgage registration must be carried out with the department specified by the local people's government at or above the county level. If the land use rights and house ownership are obtained due to the disposal of mortgaged real estate, the transfer registration shall be carried out in accordance with the provisions of this chapter.