As an essential lifeline engineering system,water distribution network should provide enough water to maintain people’s life after earthquake in addition to working under daily operation.However,the design of water distribution network usually ignores the influence of earthquake,resulting in water stoppage in large area during many recent strong earthquakes.This study introduced a seismic design approach of water distribution network,i.e.,topology optimization design.With network topology as the optimization goal and seismic reliability as the constraint,a topology optimization model for designing water distribution network under earthquake is established.Meanwhile,two element investment importance indexes,a pipeline investment importance index and a diameter investment importance index,are introduced to evaluate the importance of pipelines in water distribution network.Then,four combinational optimization algorithms,a genetic algorithm,a simulated annealing genetic algorithm,an ant colony algorithm and a particle swarm algorithm,are introduced to solve this optimization model.Moreover,these optimization algorithms are used to optimize a network with 19 nodes and 27 pipelines.The optimization results of these algorithms are compared with each other. As an essential lifeline engineering system, water distribution network should provide enough water to maintain people’s life after earthquake in addition to working under daily operation. Host, the design of water distribution network usually ignores the influence of earthquake, resulting in water stoppage in large area during many recent strong earthquakes.This study introduced a seismic design approach of water distribution network, ie, topology optimization design.With network topology as the optimization goal and seismic reliability as the constraint, a topology optimization model for designing water distribution network under earthquake is established.Meanwhile, two element investment importance indexes, a pipeline investment importance index and a diameter investment importance index, are introduced to evaluate the importance of pipelines in water distribution network.Then four combinational optimization algorithms, a genetic algorithm, a simulated annealing genetic algorithm, an ant co lony algorithm and a particle swarm algorithm, are introduced to solve this optimization model. Moreover, these optimization algorithms are used to optimize a network with 19 nodes and 27 pipelines. The optimization results of these algorithms are compared with each other.