A　genetic　algorithm　based　optimization　scheme　was　proposed　to　reduce　the　cost　of　cable　dome　structure　in　practical　engineering.　The　prestress　coefficient　and　member　sections　with　specified　profiles　were　defined　as　discrete　design　variables,　and　structural　tensioning　level　was　considered　in　the　object　function.　Taking　Geiger　and　Levy　cable　domes　as　two　examples,　the　minimum　cost　design　was　obtained　which　satisfied　constraints　of　structural　stress　and　displacement　in　a　variety　of　load　conditions,　and　sensitivity　analysis　was　adopted　to　study　the　influence　of　prestress　on　optimization　results.　The　optimization　process　was　also　carried　out　for　an　improved　structural　plan,　ridge-bar　cable　dome,　in　which　the　ridge　cables　were　replaced　with　steel　bars　capable　of　bearing　compression,　and　the　structural　cost　and　mechanical　properties　of　improved　plan　were　compared　with　the　original　cable　dome　structure.　Results　show　that　the　optimization　method　can　gain　the　minimum　cost　design　of　cable　dome　effectively　and　accurately,　and　the　internal　force　of　all　members　are　closed　to　their　limit　state.　To　guarantee　the　structural　stability　and　bearing　capacity　of　different　members,　it　is　necessary　to　consider　the　partial　factor　of　prestress　and　non-uniform　distribution　of　live　load　in　the　design　process　of　cable　domes.　Adopting　steel　bars　instead　of　ridge　cables　can　slightly　lower　the　total　cost　of　cable　dome　and　significantly　reduce　the　deflection　and　reaction　force.　©　2017,　Editorial　Department　of　Journal　of　Beijing　University　of　Technology.　All　right　reserved.