Upon the analysis of the monitoring data on underwater topography and cross-sections after the trial excavated channel of the approach channel of Toumen Port in Taizhou，we obtain the siltation characteristics of the trial excavated channel and discuss the siltation mechanism.The results show that during the monitoring period of 13 months，the trial excavated channel experiences the development process of natural and slow back-silting to alternating sudden silting and scouring to natural and slow scouring，and finally reaches a dynamic equilibrium and remains stable.The average water depth of the trial excavated channel meets the design navigation water depth requirements of 11.7 m.Under normal weather conditions，suspended sediment deposition is the main form of siltation in the trial excavated channel.Under strong wind conditions，the sediment-lifting effect of typhoons causes sudden siltation in the trial excavated channel，and a floating mud layer develops in the channel；the cold-air outbreak has a weak effect.