In this paper, a simulation model for a hybrid HVDC transmission system, which consists of a line-commutated current source rectifier and a voltage source inverter based on PWM control scheme, is proposed. Its control scheme is also designed, in which the rectifier maintains constant voltage (CV), and the inverter operates with constant DC voltage and constant AC voltage. Compared with the conventional HVDC transmission system, such hybrid HVDC transmission system can be connected to a passive load field. The performances of the hybrid HVDC transmission system is simulated and analyzed. The simulation results have shown that the model for hybrid HVDC transmission is correct and its control method is effective. At the same time, it is also proved that this kind of hybrid HVDC transmission system has some valuable operation performances, which is superior to the conventional HVDC transmission system.