Abstract: In order to enhance navigation safety,prevent and reduce maritime accidents in the bridge waterway, where is a frequently-occurring accidents area,AIS(Automatic Identification System)data are collected and analyzed from the perspective of ship behavior.Two typical indexes(i.e.course and speed)in upstream/downstream and different river seasons are analyzed to discover their impact on ship behavior.After comparing the results of normal and lognormal distributions fitting in different patterns using AIS data,the latter distribution is discovered to fit better than the former one.Moreover,the influences on ship behavior are quantified by using interval numbers of ship speed and course.The re-sults show that ship speed is influenced a lot by the dry season with a relatively high speed(i.e.[7,9]kn).Moreover, ship course is greatly influenced by the flooding season,specifically,the heading has an increasing trend when ships navi-gate from downstream to upstream,while the trend is decreasing from upstream to downstream.