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