The invention related to an economic dispatching method for a power distribution network and especially relates to a real-time distributed economic dispatching method for the power distribution network. According to the invention, the method comprises the steps: taking the minimum power generation cost as an economic dispatching target of a power 
system, wherein a power generation cost function isa secondary function of generated power; taking an external 
power grid as a virtual generator, and expressing the cost function through a secondary function, but supposing that the output power of the cost function is zero; taking the incremental cost of each generator set as a consistency variable, and enabling the incremental cost of each generator set to be convergent to a consistency value through a distributed consistency 
algorithm, thereby obtaining an optimal solution of economic dispatching. According to the invention, the external 
power grid is equivalent to the virtual generator which participates in the economic dispatching, and the method takes the incremental cost as the consistency variable. Only the active power exchanged between the power distribution network and the external 
power grid needs to be measured, and there is no need of other 
global information, thereby overcoming a difficulty that a conventional distributed economic dispatching 
algorithm needs to obtain the 
system power difference or total load.