In order to improve the dynamic response speed and its tracing performance with the target value in the VSC-HVDC transmission system，in terms of the constant DC voltage control method and constant active power method of the system, this paper comes up with corresponding improved feedforward control strategy on the basis of the traditional direct current control controlled by the double closed loop decoupling control strategy．In the constant active power control of rectifier side，a predictive signal is added to the inner current loop on the basis of the outer voltage loop to enhance the response speed of the system and compensate the hysteresis nature of the feedback signal．In the DC voltage control of inverter side，in order to increase the anti-interference performance of the DC voltage to the outside，an improved feedforward control strategy adopts the system voltage and DC current signal is introduced so that the DC voltage has a strong resistance to the external disturbance．In the end，a two-terminal VSC-HVDC model is built in PSACD/EMTDC，simulations and analyses are carried out in the system under different operating conditions．The results show that the improved feedforward control strategy has a good value fit to the target value，good robustness and rigidity of DC voltage to the external disturbance have also gotten．