In view of how to reasonably set up AIS virtual AtoN，this paper simulates and analyzes the channel capacity and system blocking rate of AIS system，taking the Yangtze River basin and Shanghai port as examples. The results show that：1）The setting of AIS virtual AtoN occupies part of the communication time to reduce the channel capacity. 2）The more the number of ships in the system，the greater the increase of system blocking rate，and the more serious the impact of AIS virtual AtoN setting on system communication. Based on this conclusion，the threshold values of the number of AIS virtual AtoN that can be set in different water conditions are analyzed，and the suggestions for reasonable setting of AIS virtual AtoN are given，which can be used as a reference for setting virtual beacons in different waters. Under the condition of ensuring less influence on ship communication，the reasonable setting of AIS virtual AtoN can better play its navigational warning function and ensure the safety of ship navigation.