Under　the　new　normal　of　China’s　development,　urban　construction　has　shifted　from　incremental　expansion　to　the　optimization　of　existing　stock.　As　the　focal　point　of　urban　stock,　old　communities　have　garnered　increasingly　in-depth　research.　Recent　studies　have　extended　their　perspectives　from　physical　spaces　to　the　interactive　relationship　between　＇space　and　behavior＇,　while　also　emphasizing　the　integration　of　qualitative　and　quantitative　analyses.　However,　existing　research　primarily　focuses　on　the　static　characteristics　of　material　spatial　environments,　neglecting　the　dynamic　interplay　between　spatial　attributes　and　social　network　relationships.　This　study　takes　the　Cangxia　Community　in　Fuzhou　as　a　case　study,　employing　social　network　analysis　(SNA)　to　construct　a　dual-network　model　of　resident　behavior　and　public　space.　Through　a　three-level　analysis　of　＇overall–subgroup–single　point＇,　the　intrinsic　relationship　between　＇space　and　behavior＇　in　old　communities　is　revealed.　The　model　demonstrates　that　resident　behavior　characteristics　are　positively　correlated　with　public　space　attributes,　namely,　the　better　the　spatial　accessibility　and　visibility,　the　higher　the　frequency　of　resident　behaviors.　However,　mismatched　spatial　nodes　also　exist,　limiting　the　synergistic　optimization　of　the　dual-network　model.　This　research　aims　to　provide　scientifically　effective　methods　and　paradigms　for　the　renewal　of　old　communities　and　the　sustainable　development　of　cities.　©　2025　by　the　authors.