Radiation pneumonitis is the most common complication and the major dose-limiting toxicity associated with radiotherapy, which can cause poor quality of life or life-threatening symptoms and might hinder the tumor-controlling effects of radiotherapy. Consequently, establishing reliable predictors for the occurrence of RP is of great significance such that the therapeutic effects of RT can be maximized while minimizing its adverse effects. The aim of this study is to figure out the biological prediction models of radiation pneumonitis.