The problem of evaluation of a multi-function phased array radarpsilas ballistic missile defense capability has been highly concerned for years. The ballistic missile defense process, in which a multi-functional phased array radar is involved, is studied by using modeling and simulation technique for radar and electronic warfare (EW) systems. Simulation models of radar and EW systems are constructed at the signal level, and simulation software is developed. In typical anti-ballistic missile scenarios under the conditions of stealth targets and electronic countermeasures, simulation experiments are conducted. Simulation results provide effective supports for the evaluation of phased array radarpsilas ballistic missile defense capabilities.