In recent years, the scale of Internet information infrastructure has expanded rapidly, and its threat assessment is becoming more and more important. Assessing the threat of Internet information infrastructure can find out the most vulnerable link in the network node and provide a reference for taking correct network security defense measures. In view of the low accuracy of current Internet information infrastructure threat assessment methods, the study combined relevant data on Internet information infrastructure and constructed a knowledge graph of basic Internet information. This study proposes an Internet infrastructure threat assessment model based on knowledge atlas. In the effectiveness analysis of the model, the most vulnerable network node was Dom5, and it was found that the vulnerability of this node was affected by Dom1, Dom2, Dom3, Dom4, Dom7, and Dom8. Subsequently, in the analysis of the application effect of the model, the average F1 value and average recall rate of the model were 96.13% and 97.26%, respectively, which were better than the comparative model. The results show that the model is effective and has practical application value. This model not only has a high accuracy rate and recall rate in identifying vulnerable nodes but also provides valuable insights for network security defense strategies. This model accurately locates vulnerable nodes, analyzes their vulnerability impacts, and takes proactive measures to enhance network security.