Based　on　the　theory　of　reliability　and　combined　with　the　fuzzy　fault　tree　analysis　method,　a　new　method　of　evaluation　and　functional　optimization　of　earthquake　resistance　and　disaster　prevention　system　is　proposed.　Based　on　the　establishment　of　fault　tree　of　the　system,　aiming　at　the　shortcomings　of　not　considering　the　fuzziness　and　failure　dependency　in　the　traditional　fault　tree　analysis,　the　reliability　vector　and　the　triangular　fuzzy　number　method　are　used　to　evaluate　the　urban　seismic　capacity.　At　the　same　time,　the　impact　of　the　failure　dependency　between　events　on　the　reliability　of　the　fault　tree　system　is　also　considered.　Combined　with　the　theory　of　reliability　allocation,　the　optimized　redistribution　quantitative　models　of　the　reliability　for　every　unit　in　the　system　are　established,　which　provides　a　complete　theoretical　method　for　the　evaluation　and　optimization　of　urban　earthquake　resistance　capacity.　Through　an　example,　the　calculation　process　of　evaluation　and　the　optimized　redistribution　of　the　reliability　are　described　in　detail.　The　research　shows　that　this　method　is　more　general,　for　it　can　overcome　the　assumption　in　traditional　method　that　the　failure　of　each　unit　is　random　and　independent　with　each　other.　Also,　it　can　find　out　the　weak　links　and　achieve　the　optimal　allocation　of　the　system.　©　2018　Disaster　Advances.　All　rights　reserved.