Data link is a communication method applied in various advanced weapon systems with the aim to exchange real-time tactical data. This system can provide commanders who scattered all over the battlefield with a complete and coherent tactical picture. Prior to bring up the requirements for data Iink, one should think from the aspect of tactics applications, considering, during a combat mission, the command and control relations between each operational unit in order to identify where the collected information should be sent to, and what information each operational unit needs. By doing so, the real-time information could be sent to the unit that most needs in a shortest period of time and made the best use of it.