Generally, you have to go to the local people's bank to exchange it. In some areas, the People's Bank of China can designate 1 and the central branches of two commercial banks for fixed-point exchange. You need to change money in these places. However, due to the fact that treasury bonds are overdue and do not bear interest, although they are overdue for a long time, they still only have interest due. Therefore, if it is not cost-effective to exchange good quality treasury bills, they can be sold in the local postal currency card market, and the price is definitely higher than that of the exchange.