In order to provide a basis for 12.5 m deepwater waterway regulation of Kou’an straight reach, considering development of port on both sides of the reach, we determined that the left flume of Manyusha shoal reach is 12.5 m deepwater waterway and the right flume is 10.5 m deepwater waterway based on the analysis of waterway conditions and evolution trend of Manyusha shoal reach, and verified the requirement of waterway arrangement under the influence of Taizhou highway bridge and waterway regulation engineering. The result indicates that the choice of 12.5 m deep-water route of Taizhou bridge left navigable sailing into the left slot is characterized by smooth transition route, thus it is a safer route layout; When the left navigable Hangkuan is insufficient, it is feasible to adopt the scheme of transiting from the right main navigable hole of Taizhou highway bridge to the left slot.