The invention discloses a voltage coordination control system and method for large-scale new energy access to a power grid. The control system comprises an AVC regulation and control master station, an AVC regional regulation and control substation, a new energy regulation and control substation and a real-time communication system. The AVC regulation and control master station is used for evaluating the dynamic reactive reserve of the power grid, and issuing a reactive voltage multi-target regulation and control instruction to the AVC regional regulation and control substation according to the power grid operation state reported by the AVC regional regulation and control substation through the real-time communication system; the AVC regional regulation and control substation is used for collecting and analyzing power grid voltage and reactive power information reported by the new energy regulation and control substation in the area in real time, and issuing a reactive control object to the new energy regulation and control substation; and the new energy regulation and control substation searches the reactive power and voltage data and controls the real-time reactive power output of the new energy plant station according to the superior instruction. The real-time communication system is used for direct data communication of all levels of the regulation and control stations. Through the unified coordination control on the reactive power of the power grid, the global stability of the power grid voltage is guaranteed.