An adaptive direct current（DC）voltage droop control strategy for sharing the unbalanced power according to the available headroom of each converter station is proposed for the voltage source converter based multi-terminal high voltage direct current（VSC-MTDC）system.The converters already operating close to the rating would share less unbalanced power than the extent of the other converters with more spare headroom，thus avoiding out of action to DC system changes which may take place with a fixed value of power-voltage droop.Finally，simulations are performed in PSCAD/EMTDC to verify the validity of the control strategy under different operating conditions.Simulation results show that the adaptive droop control strategy performs well when the VSC-MTDC system is operating under different conditions.