To improve efficiency of communication software in vessel monitoring system, a design scheme integrating three level communication architecture of server + two level clients and cloud computing platform based on Openstack is adopted. Network topology of the software is server + first level client + second level client, where communication between server and first level client( server of the sub-control center) is through TCP/IP protocol and communication between first level client and second level client is through UDP broadcast protocol in local area network of the sub-control center. For the server side, a cloud computing resource sharing system based on Openstack is realized to take full advantage of the server resource. By this way, communication server, database server, application server and AIS data distribution / decoding server can share hardware resource of multiple hosts and manage computing resources virtually, thus improving resources occupation percentage and optimizing server performance. Then three level network topology, communication process and cloud computing server are discussed in detail. Practical application shows the reliability and robustness of the software, while ensuring real-time communication of large amount data.