In view of voltage sag phenomenon in the distribution network

a kind of multi-index evaluation method based on comprehensive weight is proposed in this paper. This method selects multiple evaluation indexes to set up index set

over comes the defects of the traditional evaluation method in which only the defects at the supply side or the electricity side is considered

making evaluation results more comprehensive. It employs analytic hierarchy process（AHP）and the CRITIC method to calculate a new weight

giving full consideration to the deep inner relation between each evaluation index as well as their relative importance

making evaluation results more reasonable. After multiple Monte Carlo simulation

the composite score of each node is calculated and the sag vulnerability area intersection of weak nodes in the network is obtained. Finally

it is proved by the result that this method can accurately and effectively identify weak nodes and weak area in network

and lays the foundation for voltage sag and control.