Based on the requirements of future combat on the sea and information countermeasure of Carrier Battle Group, we primary study on air defense command and control system of carrier battle group. In the paper, we analyze process and characteristics of the air defense system. General principles of the air defense system fire command were given. In order to validate the reliability of the air defense command and control system of carrier battle group, we build the simulation platform. Base of the platform, we study defense process of electronic warfare UAV penetration. Then we study several typical scheme on the platform, and analyzed the data of simulations, simulation results had shown that the General principles of the air defense system fire command is correctly, and the target assignment process provides support for improving the combat system of Carrier Battle Group.