The rapid development of the Yangtze River Economic Belt has put forward higher requirements on the channel dimensions of the lower Yangtze River. Ascertaining the maximum stable channel depth of this reach under natural endowment is thus of great practical significance for channel planning and development potential research. Considering that the Hukou-Nanjing reach of the lower Yangtze River largely consists of braided reaches in terms of river regime characteristics，this paper proposes a calculation method for the stable channel depths of the branches on the basis of stable channel depth estimation. It then calculates the maximum stable channel depths of several typical navigation-obstructing branches and obtains a relation between the maximum stable channel depth and the flow diversion ratio of each branch of this reach. The results show that the maximum stable channel depths of the four typical navigation-obstructing branches are respectively 11.2 m（in the right branch of the Madangnan channel），9.6 m（in the Xigang branch of the Dongliu reach），12.0 m（in the Zhonggang branch of the Guichi reach），and 15.7 m（in the main branch of the Jiangxinzhou reach）.