The development of scale extension in coastal port area and enlargement of ships require higher-level port service,and the water scale is one of the main factors affecting the port service level.Based on the analysis of operation process of ship entering and leaving port in the coastal port area with different width of harbor basin,we build an Anylogic-based port navigation operation simulation model to study the influence of the width of harbor basin on the port service level.The port navigation operations under three different conditions of basin widths are simulated,and the results show that the port service level increases by 36% with the layout of medium harbor basin,of which the water area is 1.25 times as that of the narrow harbor basin,and the port service level increases by 90% with the layout of wide harbor basin,of which the water area is 1.48 times as that of the narrow harbor basin.