Distribution network planning method and system

The invention discloses a distribution network planning method and a distribution network planning system. The method comprises the following steps: determining the point distribution and net rack of a prospective high-voltage substation and the point distribution and net rack of a recent high-voltage substation according to the load prediction level in a newly established region, wherein the load prediction level comprises the substation and feeder line load level; determining a medium-voltage reliability weak link concentration region; quantitatively determining the distribution network safety weak link; and formulating a targeted distribution network planning project according to the point distribution and net rack of the prospective high-voltage substation and the point distribution and net rack of the recent high-voltage substation in the newly established region, the medium-voltage reliability problem concentration substation and the distribution network safety weak link, so that a preset reliability target is achieved, and the power supply reliability requirement is met. According to the technical scheme, the technical problems in the prior art that the power supply reliability of the distribution network planning project is low and the lean requirements of users on the power supply are effectively solved.