This　study　presents　three　static　reanalysis　methods　for　large-scale　structures　with　large　modifications　of　structural　parameters　based　on　the　Combined　Approximation　(CA)　method.　For　large-scale　structures　with　large　changes　in　the　design,　the　Combined　Approximation　method　can　not　provide　enough　accurate　results.　To　improve　the　accuracy　of　the　results　in　reanalysis　of　the　modified　structure,　three　CA-based　static　reanalysis　methods　are　presented　by　introducing　several　strategies,　such　as　displacement　iterative　correction　and　stiffness　progressive　approximation.　Two　numerical　examples　are　presented　to　demonstrate　the　validity　and　the　improvement　of　the　proposed　methods,　and　the　results　show　that　the　methods　given　can　provide　accurate　approximations　and　can　significantly　reduce　the　computational　effort　involved　in　reanalysis　of　large-scale　structures　with　large　modifications.　Comparisons　of　the　computational　costs　of　these　three　presented　methods　are　made.