Different definitions and different properties.

1. Different definitions: The spot exchange rate refers to the actual transaction exchange rate when buying and selling foreign exchange, that is, the price paid to buy one currency of another currency. The central parity rate is the benchmark exchange rate determined by commercial banks based on market supply and demand when buying and selling foreign exchange.

2. Different nature: The spot exchange rate is the actual transaction exchange rate, which is used for spot foreign exchange transactions and reflects the actual transaction price in the market. The middle price is the base exchange rate, used as a reference and for calculating other exchange rates, and is not necessarily the actual transaction exchange rate.