The cryptocurrency trading pair #交易对 refers to the exchange relationship between two types of currencies, such as BTC/USDT which indicates using USDT to purchase BTC. Common trading pairs include coin-to-coin trading (such as ETH/BTC), stablecoin trading (such as BTC/USDT), and fiat trading (such as BTC/USD). When choosing a trading pair, one should consider liquidity, trading depth, and volatility. Stablecoin trading pairs are convenient for calculating profits and are suitable for most investors; whereas coin-to-coin trading pairs are suitable for arbitrage and asset conversion. Choosing the right trading pair is key to improving efficiency and profitability.