This study analyzes the regulations converting Simayin(司碼銀) and 8-real coin into Kupingyin(庫平銀) and, through the procedures for assessing and converting actual customs duties after the payment of tariffs, examines the Yuehaiguan(粵海關) weights distinguishing them from the Kuping(庫平). The deputy customs duty structure of the Canton System created a subtle weight difference among Hubu(戶部), Yuehaiguan(粵海關), and Hong Merchants(行商). Analyzing this distinction, endeavors were made to trace the roots of the currency used in Chinese Maritime Customs, known as Haiguanliang(海關兩), back to the Canton System. As a result of the analysis, it was confirmed that the independent weights of Yuehaiguan(粵海關) distributed nationwide from Hubu(戶部) were different from Kuping(庫平), and it was conceptualized as ‘Yuehaiguanping(粵海關平)’. Yuehaiguanping(粵海關平) served as the weight standard for foreign trade and customs administration, differing from the certified weighing system represented by Yuehaiguankuping(粵海關庫平) used for accounting purposes. The weight system used by merchants, known as Simaping(司碼平), is considered to have originated from Yuehaiguanping(粵海關平), ultimately concluding that these two systems are essentially identical.“Previous studies on understanding Chinese Maritime Customs' generally share the perspective that, despite subtle differences, the Western-style customs system was introduced to China in a unidirectional process. The emergence of the currency Haiguanliang(海關兩) in Chinese Maritime Customs is considered a crucial mechanism for imperial powers to control Chinese customs. However, if we exclude the wounded pride of the Chinese people from the starting point of semi-colonialism, researchers need to explore the reasons why the Western customs system could seamlessly integrate into China's institutions without encountering significant resistance or conflict. The author aims to present a new approach to understanding Chinese Maritime Customs, which inherits the deputy customs duty structure of the Canton System. The form of outsourcing tax and customs duty operations to the private sector was not unfamiliar in pre-modern China. The idea of entrusting customs administration to tax professionals at that time was quite acceptable and feasible. The dismantling of the Canton System and the emergence of Chinese Maritime Customs signify not only the ultimate end of monopoly trade but also a significant transformation from the traditional Queguantizhi(榷關體制) to the Haiguantizhi(海關體制). This process can be understood as a major shift that could be based on the basic framework of the Canton System.