清代榷关制度的核心内容是税收 ,而税收的核心内容就是“额税”的确定 ;“额税”的确定始于明朝的钞关。清朝统治者在对明代钞关制度的继承与发展中 ,首要任务就是对明末钞关“额税”重新核定以及对清代新增榷关额税的确定。本文考察的清代榷关的“额税”专指作为其正项收入的正额和盈余两部分。 The core content of the customs clearance system in the Qing Dynasty was taxation, while the core of taxation was the determination of “amount tax”; the determination of “amount tax” began with the currency clearance of the Ming Dynasty. In the inheritance and development of the banknote clearance system in the Ming Dynasty, the chief task of the Qing rulers was to re-verify the “amount tax” at the end of the Ming Dynasty and confirm the new amount of customs duty on the Qing Dynasty. In this paper, the “tax on duty” in the Qing Dynasty was specifically defined as the positive sum and the surplus of the positive income.