This paper mainly explores the navigable long-term level of Fanshi waterway required for the Shenzhen-Zhongshan Passageway crossing the Pearl River Project (hereinafter referred to as “S-Z Passageway”) in order to avoid the influence of the S-Z Passageway on the safety and smoothness of the navigation of vessels on both sides of the Pearl River estuary.The paper comprehensively considers the current navigable condition of the Pearl River estuary and the long-term ports planning,and puts forward the necessity of reserving the navigable grade of 100,000-ton class for Fanshi waterway.Using numerical simulation and comprehensive geophysical prospecting,we analyze and demonstrate the deep trough stability of Fanshi waterway,water flow conditions,channel dredging and channel maintenance.At the same time,compared with the typical large-scale domestic ports,we clarifies the scale of the port throughput requirements for channel resources,and put forward the factors which should be considered in demonstration of the long-term level of Fanshi waterway.We think that it is necessary and feasible for Fanshi waterway to reserve channel level of 100,000-ton class.