The invention discloses a method for controlling drooping of VSC-HVDC. According to the method, a VSC is used for simulating the external characteristic of a synchronous generator, the synchronous generator can achieve networking power generation and also can directly supply power to a passive island, and therefore the VSC-HVDC control strategy without switching a controller structure can be designed by the aid of the control characteristic of the synchronous generator. According to the method, the VSC can actively control the frequency, the phase and the amplitude of AC voltage modulation waveforms, so that it is guaranteed that the stable voltage waveforms can be provided in the process of providing power for a passive network. In addition, the method enables the VSC to have a frequency deviating regulation characteristic so as to be adaptive to load fluctuation of an AC network during networking operation. Accordingly, the method for controlling drooping of the VSC-HVDC is suitable for a VSC-HVDC networking operation mode and an islanding operation mode, and it can be guaranteed that the VSC-HVDC is smoothly and stably switched between the two operation modes.