The invention discloses a reactive power synergic control method and system of a large-scale energy storage participating in new energy field station. According to the method, an energy storage converter is divided to active power synergic control group and a reactive power synergic control group, wherein the active power synergic control group is in a way that an active power is controlled with full capacity, smooth wind light output is performed and an active power target value of the full station is traced, and the reactive power synergic control group is in a way that a reactive power is controlled with full capacity, a reactive power voltage demand of a grid-connected point is traced, and reactive power standby of each reactive power source in the new energy field station is optimized. By the method, active power and reactive power decoupling control of large-scale energy storage under different control periods is achieved, the influence of active power and reactive power simultaneous control of an energy storage converter on stability and accuracy of active power control can be prevented, the smooth wind light output fluctuation of the energy storage is achieved, the influence of active power fluctuation on a voltage of the grid-connected point is reduced, the reactive power target control of the energy storage participating in tracing the voltage of the grid-connected point is also achieved, enough reactive power standby is reserved, and the grid-connected running stability of new energy power generation is improved.