The invention discloses an impedance-self-adaptive inverter reactive voltage control parameter optimization method which is characterized in that a power distribution network Jacobi matrix and a reactive voltage amplitude sensitivity matrix are obtained via load flow calculation firstly; then coupling decomposition is performed on the reactive voltage amplitude sensitivity matrix by utilizing an epsilon decoupling algorithm and a power distribution network comprising distributed photovoltaic is correspondingly divided into subareas which are not mutually overlapped; then short-circuit impedance of each inverter access point is measured in an online and real-time way via an impedance self-adaptive method, and dead zone width D controlled by inverter reactive voltage V(Q) is confirmed by the measured short-circuit impedance; and finally optimization and setting of the dead zone width D controlled by the inverter V(Q) of each subarea are performed with the minimal whole year voltage fluctuation of each subarea of the power distribution network, the minimal reactive power demand and the lowest network loss acting as the objectives. A problem of inverter parameter online self-adaptive setting is solved so that photovoltaic consumption capacity of the power distribution network is enhanced and distributed photovoltaic safe and friendly grid connection is also realized.