Within　the　scope　of　urban　service　area,　the　seismic　failure　of　buried　pipelines　is　interdependent　to　each　other　in　a　pipeline　network　system,　which　is　caused　by　similar　structural　parameters　of　pipelines　and　the　spatial　correlation　of　ground　motion　intensities.　In　present　paper,　a　Monte　Carlo　simulation　(MCS)　strategy　for　seismic　reliability　evaluation　of　the　pipeline　networks　under　correlated　ground　motions　is　proposed.　The　correlated　coefficients　of　pipeline　failure　events,　affected　by　spatial　correlated　ground　motions,　are　determined　according　to　the　measures　presented　by　Lim　and　Song.　To　calculate　pipeline　network　reliability,　in　the　MCS　method　proposed　in　present　paper,　the　seismic　failure　events　of　pipelines　are　firstly　taken　as　correlated　random　variables　and　transformed　into　uncorrelated　random　variables　by　orthogonal　transformation.　The　validity　of　the　proposed　MCS　method　is　verified　by　results　comparison　between　the　analytical　method　and　the　MCS　method.　©　2017　American　Society　of　Civil　Engineers.