Damage probability of metal storm weapon based on barrage firing was evaluated. For ascertaining the position relationship between intercept barrage and target projection on surface of barrage firing and obtaining the hitting probability of intercept barrage to target, the author generally considered the errors of fire data, errors of target point and errors of dispersion of metal storm weapon. By inducting the pills of damage target demand, the damage probability model about metal storm weapon based on barrage firing was established and the simulation example was given. The model gives theoretical support for performance evaluation and operational application of metal storm weapon.