The Low-rate Denial of Service (LDoS) attacks reduce network services capabilities by periodically sending high intensity pulse data flows. For the hidden performance of LDoS attacks, it is more difficult for traditional DoS detection methods to detect. At the same time the accuracy of the current detection methods for the LDoS attacks is relatively low. However, when the LDoS attacks occur, the frequency distribution and the fluctuation pattern of the TCP traffic have a special change. As the fact that the LDoS attacks led to the abnormal frequency distribution and the abnormal fluctuation pattern of the TCP traffic, the authors propose a New Collaborative Detection Method (NCDM) for LDoS attacks.