This　paper　proposes　a　personalized　method　to　estimate　blood　flow　distribution　based　on　the　cross-sectional　area　of　the　left-right　coronary　artery　openings.　According　to　the　cross-sectional　area　of　the　left-right　coronary　artery　in　30　cases,　a　personalized　flow　distribution　model　was　derived.　A　0D/3D　geometric　multiscale　model　was　used　for　the　numerical　simulation　of　FFR.　To　evaluate　the　accuracy　of　the　cross-sectional　area　method,　invasive　FFR　was　used　as　the　standard.　The　diagnostic　efficiency　of　the　proposed　method　was　verified　through　the　simulation　results　of　the　volume　and　the　fixed　ratio　methods.　The　flow　of　the　left-right　coronary　artery　was　proportional　to　the　3/4　power　of　the　cross-sectional　area.　The　95%　LOA　between　the　cross-sectional　area　method,　volume　method,　fixed　ratio　method　and　FFR　were-0.06　([-0.22,　0.10]),-0.03　([-0.35,　0.28]),　and-0.05　([-0.30,　0.20]),　the　accuracy　values　were　94.44%,　77.78%,　and　77.78%,　respectively.　Flow　distribution　based　on　the　cross-sectional　area　represents　the　supply　and　demand　relationship　of　the　myocardium.　The　flow　of　the　left-right　coronary　arteries　is　proportional　to　the　3/4　exponent　of　the　cross-sectional　area,　which　affects　the　accuracy　of　FFRCT　by　affecting　the　exit　boundary　conditions　of　the　0D/3D　model.　©　2022　World　Scientific　Publishing　Company.