The invention discloses a distributed photovoltaic cluster coordinated optimization control method and a distributed photovoltaic cluster coordinated optimization control system.The method includes subjecting n load nodes in a power distribution system to decoupling partitioning, and partitioning the n load nodes into N sub partitions; if node voltage of the power distribution system is in an off-normal condition, determining M sub partitions with off-normal node voltage from the N sub partitions, and determining control priority of each of the M sub partitions; sequentially subjecting the M sub partitions to coordinated optimization control of the node voltage according to a descending order of the control priorities so as to regulate the node voltage of every load node in the M sub partitions to a normal pressure range.The distributed photovoltaic cluster coordinated optimization control method and the distributed photovoltaic cluster coordinated optimization control system have the advantage that voltage regulation time can be shortened substantially, so that voltage control efficiency is improved.