Some uncertain factors of the power grid, such as construction conditions, surrounding environment,etc., are not considered in traditional network planning methods, so that it is difficult to achieve the expected results. A new urban distribution network planning method is proposed, where the boundary elements including load development and power grid construction conditions are considered in determining the locations, capacities and service area of the substations. Then according to the locations and the capacities of substations, the 20/10 kV lines, the medium voltage distribution transformer capacities, the numbers of switching units and the reactive power compensation capacities are estimated. Finally, the assessment, validation and correction of the planed program are implemented. The application results show that the approach is consistent with engineering practice, which has a certain practicality.