Voltage qualified and reactive power is the basic condition for the safe and stable operation of power system. It is important to determine the appropriate reactive power compensation method and voltage regulation scheme for power network operation. Compared with the traditional nine-domain graph control strategy, the reactive power voltage control strategy based on the three-dimensional nine-domain diagram is proposed. The time axis is added while the upper and lower limits of the voltage in different time zones (time zones) is changing. Based on the global reactive power optimization model of load forecasting, the expected adjustment scheme of each substation in the distribution network is obtained, which divides the day into several time zones and obtains the operating boundary of each time zone according to the optimization curve. The reactive power and voltage control strategy of substation based on three - dimensional nine - domain diagram combines the merits of dynamic reactive power optimization and real - time control, which not only avoids the frequent adjustment of reactive power compensation equipment and main transformer tap ,but also improve the economic operation of substation.