Cox regression model is the main method to analyze survival data, and it is widely used in medical research to study the relationship between patient survival time and multiple risk factors or prognostic factors. In order to ensure the validity of the model and the accuracy of the results, certain prerequisites must be met, including the conditions common to all regression models and the conditions aimed at the unique attributes of survival data and Cox regression model. These conditions will affect the interpretability of the model and the reliability of the research conclusions.