Aiming at the problem of bad actual effective of assessing weapon system utilization in the air combat countering, the download flow of data link information was designed, the mechanism of data delay was analyzed, both of which were based on analyzing kinds of data necessary in assessing missile utilizations. Under the condition of typical manipulation, the striking area and killing probability area of missile were employed to evaluate the launched condition. According to the flight index and weapon index from data link, the virtual flying track was depicted for accessing the attack result. Through setting three groups of simulating scene, the different shooting probability could be obtained by different launched area and different defense. The validity of the real-time arithmetic was verified by the result.