Purpose　-　The　purpose　of　this　paper　is　to　provide　an　optimization　algorithm　for　a　large-span　suspendome　which　is　a　spatial　prestressed　structure　with　complex　mechanical　characteristics.　The　algorithm　optimizes　the　cable　tension,　the　dimension　of　components,　the　shape　parameters　of　structure　simultaneously.　Design/methodology/approach　-　With　the　span-to-rise　ratio,　the　length　of　the　strut,　the　cable　tension,　the　cross-sectional　area　of　the　cables　and　the　cross-sectional　size　of　steel　members　as　design　variables　and　the　gross　mass　of　entire　structure　as　the　objective　function,　a　mathematical　optimization　method　was　proposed　in　the　paper　based　on　the　hybridization　of　full　stress　and　particle　swarm　optimization　(PSO).　Findings　-　By　using　the　improved　PSO　algorithm,　the　coupling　problem　of　the　three　types　of　design　variables　was　resolved:　the　cable　tension　and　the　size　and　shape　of　the　structure　were　optimized　simultaneously　for　a　suspendome.　A　program　was　compiled　according　to　this　method　and　was　used　for　a　large-span　suspendome.　The　optimization　results　of　the　suspendome　demonstrates　that　the　method　proposed　in　the　paper　has　the　advantages　of　high　efficiency,　rapid　convergence,　and　general　applicability,　which　enable　it　to　be　used　for　the　optimization　of　various　types　of　prestressed　steel　structures.　Originality/value　-　The　optimization　program　has　more　general　parameters,　which　can　be　used　to　optimize　suspendome　with　different　spans,　different　lattice　divisions,　and　different　cable-layouts.　In　addition　to　the　strength　of　steel　and　cable,　the　integral　stability　of　the　members,　the　deformation　of　the　structure　and　the　geometrical　and　material　nonlinearity　were　considered　in　this　algorithm　and　program.　The　optimization　result　was　compared　to　the　design　of　an　actual　large-span　suspendome　engineering　project.