Abstract: On-load tap-changer (OLTC) is the core component of converter transformer, and its reliable switching process is related to the safety of converter. However, at present, OLTCs operated in ultra-high voltage converter transformers in domestic are completely dependent on imports. Obtaining transient characteristics data of OLTC in different operating states through simulation is the basis for supporting the design of key electrical parameters of OLTC and localization manufacturing. The classical OLTC models only change the transformer ratio or simulate the single-stage switching process, which is difficult to meet the requirements of voltage adjustment of full-range and synchronous acquisition of transient characteristics data of all taps, resulting in the lack of sufficient simulation data support for OLTC design optimization, parameter selection and fault analysis. In this paper, the equivalent circuit models of diverter switch and change-over selector were established based on vacuum OLTC, and the hierarchical control system was established according to the complex voltage regulation function of OLTC. Secondly, an AC simulation system was built in PSCAD to obtain the transient characteristic data waveform of on-load voltage regulation process. Compared with the analytical calculation of voltage and current, the error is less than 0.2%, which proves that the model meets the accuracy requirements of OLTC electromagnetic transient simulation research. Finally, the cyclic voltage regulation simulation was carried out to obtain the load voltage data and waveform. The results show that the OLTC model proposed in this paper can receive external control signals and perform full-range voltage regulation and change-over simulation analysis, which can provide a basic model for OLTC voltage regulation research, fault tracing analysis and transition resistance design and selection.