The invention relates to the technical field of optimal dispatching of a power system, in particular to a three-tier optimal dispatching method of an active distribution network based on energy storage time-sharing state decision-making. The method comprises the steps of comprehensively considering of a load and renewable energy power generation curve fluctuations, calculating a reference power value for the division of states of charge and discharge of energy storage, and then providing the division of time periods of charge and discharge of energy storage devices in each region; with the goal of minimizing the network loss, considering renewable energy, network security and regional tie line power constraints and combined with the time periods of charge and discharge of energy storage, calculating a backbone network dispatching plan and each regional tie line power; and with the goal of minimizing the generation cost, combined with the time periods of charge and discharge of energy storage and each regional tie line power and considering distributed power supply and network security constraints, performing the optimal dispatching of resources in the regions. The method of the invention can prolong the battery life, makes the strategy calculation simple and is highly practical.