Flexible assessment is a comprehensive evaluation method which meets the requirements of future power grid development. This paper proposes the concept of passive and active flexibility to study the uncertainty and initiative elements in the distribution network and forms a calculation model for flexible assessment. At the same time

it proposes the computational flow based on the improved discrete implicit enumeration(DIEM)method. Through the evaluation and matching of flexible indicators

combined with the flexible level calculation of node and N-k verification of line

the weakness of distribution network could be explored. Combined with the analysis of the example

it is shown that the propoesed method can improve the reliability and safety of the system.