The best is to read these instructions and follow the outline of this text. The effectiveness evaluation of Network Countermeasure (NCM) is a multi-level and multi-index problem. In order to objectively and accurately evaluate the NCM effectiveness, an index system for the NCM effectiveness evaluation is set up, and a SOM-BP cloud neural network evaluation method which combined cloud theory and neural network is presented. This evaluation method has not only randomness and fuzziness of cloud theory, but also the learning and remembering ability of neural network. Using this Method to evaluate the NCM effectiveness, we find this method has the advantage of fast convergence, few iterations, and high accuracy.