The invention discloses a coordination control method for dynamic replacing continuous reactive with discrete reactive. According to the invention, the method achieves coordination control of continuous devices and discrete devices by performing dynamic replacing. When a current AVC system is connected to a SVG device, the AVC system real-time monitors real-time reactive power output of the SVG device and operation information thereof. The bus voltage corresponding to the SVG is controlled by the SVG device. When the real-time reactive power output of the SVG device reaches the capacities of a capacitor/electric reactor, the SVG output is replaced by inputting or retreating the corresponding capacitor/electric reactor, such that the SVG maintains the maximum backup capacity, and the method for performing mutual coordination between an original discrete reactive power compensation device and a newly added SVG device of the AVC system. Eventually, the system herein maintains the maximum reactive backup, effectively prevents a power grid from being influenced by sudden changes of the voltage, and ensures the safety of the power grid.