Computer network virus has been manufactured in bulk, which can affect the normal work and study of people, and therefore the defense and detection of computer network virus should be concerned, advanced defense ability of computer network virus under the environment of computer internet can be improved. Firstly, the basic characteristics of computer network virus are analyzed. Secondly, main computer network virus propagation models are studied. Thirdly, active defense technology and detection model of computer network virus are established based on supported vector machine, and corresponding algorithm procedure is constructed. Finally, the simulation experiments are carried out, and results show that the detection model can obtain better detection effect of the computer network virus.