"Deposit" refers to a certain amount of money that one party agrees to pay to the other party as security for creditor's rights. It belongs to a legal way of guarantee, and its purpose is to urge debtors to perform their debts and ensure the realization of creditor's rights. When signing a contract, the deposit must be agreed in writing, as well as the amount and delivery time of the deposit. If the party paying the deposit fails to perform the debt, it has no right to ask the other party to return the deposit; If the party who accepts the deposit fails to perform the debt, it is necessary to double the debt to the other party. After the debtor performs the debt, the deposit shall be taken as the price or recovered as agreed. Not all "deposits" are non-refundable. Article 22 of China's "Measures for the Administration of Commercial Housing Sales" stipulates that developers may not sell commercial housing or charge any prepayment fees if they do not meet the conditions for commercial housing sales. Therefore, if the commercial housing does not meet the sales conditions and the buyers have paid the "down payment", the developer should unconditionally refund the down payment to the buyers regardless of whether the two parties agree to refund the "down payment". In addition, according to Article 4 of the Interpretation of the Supreme People's Court on Several Issues Concerning the Application of Laws in the Trial of Disputes over Commercial Housing Sales Contracts, if the commercial housing sales contract cannot be concluded due to reasons not attributable to both parties, the seller shall also return the deposit.