The invention discloses a reactive voltage coordination control method based on a flexible multi-state switch (FMSS). Aiming at a selected power distribution system, the minimum index weight coefficient of the sum of all node voltage deviations and the minimum index weight coefficient of power losses are determined according to different control targets; the reactive voltage coordination control objective function of a power distribution system feeder line group is built according to the weight coefficients; constraint conditions of the power flow constraint, the control variable constraint and the security constraint are built, and a feeder line group reactive voltage coordination control optimization model constituted by the objective function and all the constraint conditions and basedon the FMSS is obtained; and aiming at the optimization model, solving is carried out to obtain the objective function value, reactive compensation quantities of all ports of the FMSS and all the nodevoltages of the power distribution system so as to achieve reactive voltage coordination control. The power distribution network feeder line group serves as a whole for voltage management, reactive output of the feeder line group is coordinated, and the voltage level of a whole regional power distribution network is effectively improved.