Legal analysis: buying a mortgaged house can be mortgaged. Mortgage, as the name implies, means that the borrower sells the property as collateral within the repayment period of personal housing loan, and the property buyer continues to repay the seller's unexpired loan with the consent of the loan bank. In short, if the mortgaged property is bought and sold again, the buyer of the property needs to continue to repay the mortgage of the seller.

Legal basis: Civil Code of People's Republic of China (PRC).

Article 667 A loan contract is a contract in which the borrower borrows money from the lender, repays the loan at maturity and pays interest.

Article 680 usury is prohibited and the loan interest rate shall not violate the relevant provisions of the state. If there is no agreement on the payment of interest in the loan contract, it shall be deemed that there is no interest. If the loan contract does not specify the payment method of interest, and the parties cannot reach a supplementary agreement, the interest shall be determined according to the local or the parties' trading methods, trading habits, market interest rates and other factors; Loans between natural persons are regarded as interest-free.