The deployment of the AIS (Automatic Identification System) on vessels allowed grasp of the status information of the sea area from ship aspect each other or the land receiving station. AIS data include effective information, but those are not utilized enough. In this study, we proposed a mesh-data-method of the congestion analysis of vessel traffic with AIS data, and examined the movement of the vessels around the marine construction site at east side area of Kita-kyushu airport. As results, it was shown that this method was effective to get the congestion area and the status of vessels at the time of the stormy weather. Therefore this method would be useful for drafting of a safety navigation plan of the work ships.