The invention discloses a voltage control method and system for a high-voltage direct-current power transmission end. The method comprises the steps of judging whether the transmission end is in an isolated island operation state or not; in an isolated island mode, performing active and reactive cooperative control based on adaptive voltage-reactive power sensitivity and voltage-active power sensitivity; in a networking mode, performing reactive voltage control according to a normal voltage regulation coefficient; according to a reactive power distribution method, calculating a reactive power setting value of each AVC (Automated Voltage Control) unit; and finally, performing local closed-loop control according to the reactive power setting value at an excitation regulator of each AVC unit. According to the voltage control method and system, the drastic fluctuation of a voltage of a high-voltage bus of a power plant in the isolated island mode due to AVC coefficient mismatching and active regulation is avoided according to different running conditions of a high-voltage direct-current power transmission end system. The voltage control method and system can be widely applied to the field of AVC of power systems.