Abstract: Transmit delay of message has great influence on its tactical value in datalink system. This paper analyzed the message transmit process in datalink system. A datalink system simulation platform was established and multi-net datalink topology, communication protocol, communication route and message generating were built. I'he transformation process of message format and ways of transmitting were analyzed in details. The message delay, response time and delay variation under different transmitting ways were compared using above models. Simulation results show that the indexes are significantly influenced by such factors as number of nodes,message transmitting way and service strategy of nodes.

Key words: Datalink system, Time delay, Simulation, OPNET