Cable　dome　structure　is　a　large-span　spatial　structure　with　high　structural　efficiency,　which　is　suitable　for　large-span　roof　structure.　In　order　to　compensate　the　weaknesses　of　traditional　cable　dome　and　enrich　cable　dome　structure　schemes,　a　new　type　of　cable　dome,　ridge　tube　cable　dome　with　annular　struts,　was　proposed　by　the　authors　of　this　paper.　Compared　with　the　traditional　cable　domes,　the　structure　avoids　the　disadvantage　of　ridge　cable　easy　relaxation,　has　greater　whole　rigidity　and　good　static　performance,　and　relatively　less　construction　difficulty.　The　cable　dome　structure　and　the　whole　rigidity　are　mainly　determined　by　the　prestress　distribution,　so　force-finding　analysis　is　the　key　to　the　new　cable　dome　research.　In　this　paper,　the　redundant　constraint　was　replaced　by　constraint　force,　and　according　to　the　node　equilibrium　relationship　and　considering　self-weight,　the　prestress　distribution　calculation　formulas　of　the　ridge　tube　cable　dome　with　annular　struts　were　deduced.　The　calculation　method　reduced　the　operation　cost,　made　the　horizontal　force　and　vertical　force　transfer　in　the　internal　structure　clear,　and　made　the　calculation　convenient　for　engineers　both　by　hand　and　by　computer.　Simulation　results　using　ANSYS　finite-element　iteration　method　verified　the　accuracy　of　the　calculation　formulas.　Using　derived　calculation　formulas,　the　prestress　calculation　table　of　the　ridge　tube　cable　dome　with　annular　struts,　with　self-weight,　and　under　different　constraint　force　level　was　obtained　to　provide　reference　for　engineering　design　and　study　the　mechanical　properties.