The information security is an issue of serious global concern. has become a very important and critical issue in network, data and information security. An Intrusion detection system collects and analyzes information from different areas within a computer or a network to identify possible security threats that include threats from both outside as well as inside the organization. The Intrusion detection system deals with large amount of data which contains various irrelevant and redundant features resulting in increased processing time and low detection rate. Therefore feature reduction plays an important role in intrusion detection..In this paper an improvement is suggested to SVD data reduction method and implemented with Back-Propagation algorithm to detect different types of attacks .the performance is evaluated using detection rate, error rate and accuracy