Pre-sale house, a term in the real estate market, is an investment tool of real estate futures, which refers to the unfinished real estate development projects that are pre-sold. Housing pre-sale permit is commonly known as uncompleted residential flats, also known as uncompleted residential flats. In Chinese mainland, the auction stage begins with the developer obtaining the pre-sale permit of commercial housing. After the house is completed, the developer completes the initial registration of house ownership in the local housing management department and obtains the real estate license (large production certificate), and the house becomes an existing house.