Due to the absence of shoreline resources,harbor channel is occupied by the turning area to make use of natural condition.Ship berthing and unberthing has an impact on ship navigation,which leads to traffic capacity reduction.This paper uses discrete event simulation theory to simulate the system which includes ship berthing,departing and navigation.Taking Wusong cruise terminal for example,this paper gives a quantitative analysis to the influence of ship berthing and unberthing at traffic capacity,which can provide reference for planning terminal and coastal line.