Abstract: At present, there are two HVDC technical routes of HVDC control system in China, one is the HVDC control system based on limit by the ABB, NARI, and the other is the HVDC control system based on selection by the SIEMENS, XJ. The former has got a mature electromechanical transient simulation model, while modeling of the latter still lacks in-depth researches. It is usually replaced by a HVDC control system model based on limit. There is still a great difference between the simulation results and the actual characteristics, which cannot meet the needs of the power system security and stability calculation. This paper summarizes the electromechanical transient modeling principle of the HVDC transmission systems, establishes a refined model of the HVDC control systems based on selection; The paper proposes a key parameter screen and verification method based on the measured data and the trajectory sensitivity. This new modeling method is implemented in the general power system simulation program PSD-ST in China. Finally, the correctness of the model is verified by the manufacturer electromagnetic transient simulation results. The results of this paper will solve the problem of the lack of HVDC control system model, and effectively improve the simulation accuracy of the electromechanical transient simulation program.