The invention discloses a power distribution network dynamic state reconstruction method based on varying load distribution characters. According to the method, a load distribution change degree index is used for guiding time interval division to obtain an optimized time interval number. Meanwhile, a multi-period coding method is adopted to enable time interval on-off states to be cooperated, and a handling method of a distribution type power source in the dynamic state reconstruction is provided. According to the power distribution network dynamic state reconstruction method, the reasonable time interval number is selected to enable the total cost of network loss and on-off operation to be lowest.