With continuous development of science and technology, actual data integration and operating path also change greatly. To better improve transmission accuracy of overall data information, and guarantee optimal establishment of computer network security system, accuracy of overall system can improve fundamentally and more efficient computer security treatment measures can be established only when efficient network model operates. This paper simply analyzes the connotation of computer network security risk assessment model, intensively interprets the principle of fuzzy theory and composition of neural network model and finally discusses neural network model of fuzzy theory and fusion system of computer network security. This paper aims to verify system security performance through effective data analysis.