The disaster bearing capability of a city or region mainly focuses on the infrastructure

and the most important part of which is the lifeline system.It was demanded that besides the network characteristics such as complexity

proportionality and reliability

the correlativity among the sub-systems should be considered

which weakens the disaster bearing capability of the whole lifeline system.Due to the complex system brittleness theory and the brittleness link entropy method

the correlativity of the whole lifeline system was estimated and evaluated by using the system integrate brittleness link entropy and the vulnerability of the whole lifeline system was quantized through judging the interacting relationship among the sub-systems.As results

the electronic power system in the example was most deeply affected by other sub-systems wrecked by disaster

and the water supply system should be resumed first after disaster for the disaster has a certain effect on it.It was proved that this method could provide reference and direction for optimizing system organization management

controlling the repair work after disaster and coordinating the relationship of sub-systems.