Abstract: Objective To accelerate the generalization and application of multistate Cox model with time-dependent covariates during the epidemiological studies on chronic diseases.Methods Firstly introducing the basic principle of multistate Cox model with time-dependent covariates,and then applying to factors in influencing the various stages of type diabetes mellitus.Results The results gained by applying multistate Cox model with time-dependent covariates to study facotrs influencing the various stages of type 2 diabetes mellitus are satisfying.Conclusion Multistate Cox model with time-dependnet covariates is an avaliable tool during epidemiological study on chronic diseases.