The invention relates to a method and a device for dynamically evaluating the reliability of a network. The method comprises the following steps: I, capturing network
topological information; II, judging whether the first evaluation is carried out, executing the step III if yes, and executing the step VI if no; III, determining a source point and a targe node of the network to be evaluated; IV, acquiring network fault data and creating a
database; V, obtaining a network path function OBDD (Ordered
Binary Decision Diagram), evaluating the reliability of the network by an OBDD-based side expansion
algorithm and entering the step IX; VI, searching the variation of the network
topological information; VII, acquiring newly increased fault data and inputting the newly increased fault data into the
database; VIII, evaluating the reliability of the network by the network path function OBDD obtained in the last evaluation process and an OBDD-based dynamic
evaluation algorithm; and IX, outputting a network reliability
evaluation result and an evaluation suggestion. The device comprises a topological analysis unit, a fault
data acquisition unit and a reliability dynamic evaluation unit. The method and the device are suitable for the network which is dynamically changed and can be used for rapidly and efficiently evaluating the reliability of the network; and the repeated calculation is avoided and the efficiency is improved. The method and the device are suitable for various network systems.