Abstract:Neural networks have good learning and associative memory abilities and have been widely applied to various fields. We employed the Backpropagation Neural Network (BPNN) to replace the fuzzy methods of the Intelligent Intrusion Detection, Decision, Response System (I 2 D 2 RS) [5] to decide the intrusion. Through this improvement the processing of the system was simplified and the performance of the system was enhanced in the intrusion decision. The effectivities of these improvements were confirmed with the experiments.