Abstract: The variety of transformers is numerious, which are widely used in power system and serve as the core components. The flexible and variable operating scenarios require transformers to withstand complex electromagnetic transient impacts, which pose significant challenges to the safe and stable operation of transformers. Constructing an electromagnetic transient model for transformers is crucial for accurately analyzing the physical processes and characteristics of electromagnetic transients, which serves as the foundation for the optimal design, transient control, and safe operation of transformers. We categorize the electromagnetic transient models of transformers into low-frequency models, high-frequency models, and wideband models based on their applicable frequency ranges. First, we introduce the existing mainstream low-frequency circuit models of transformers including model structure, parameter identification, application scope, limitations, and so on. Moreover, we focus on the parameter measurement and characterization methods of the nonlinear excitation branch of core, as well as the dynamic coupling methods with the tap-changing model. Next, we present the existing high-frequency circuit models of transformers, including black-box and white-box models, and compare and summarize the different methods. Furthermore, we introduce wideband models that simultaneously characterizes both iron core nonlinearity and frequency-dependent characteristic. Finally, we propose application suggestions of models in various electromagnetic transient impact scenarios, and present an outlook on the future research directions for the construction of electromagnetic transient models of transformers.