A　suction　caisson　can　be　extracted　by　applying　reverse　pumping　water,　which　cannot　be　regarded　as　the　reverse　process　of　installation　because　of　the　dramatically　different　soil-structure　interaction　behavior.　Model　tests　were　first　carried　out　in　this　study　to　investigate　the　extraction　behavior　of　the　modified　suction　caisson　(MSC)　and　the　regular　suction　caisson　(RSC)　in　sand　by　reverse　pumping　water.　The　effects　of　the　installation　ways　(suction-assisted　or　jacking　installation)　and　the　reverse　pumping　rate　on　the　variations　of　the　over-pressure　resulting　form　reverse　pumping　water　were　investigated.　It　was　found　that　neither　the　RSC　nor　the　MSC　can　be　fully　extracted　from　sand.　When　the　maximum　extraction　displacement　is　obtained,　the　hydraulic　gradient　of　the　sand　in　the　suction　caisson　reaches　the　critical　value,　leading　to　seepage　failure.　In　addition,　the　maximum　extraction　displacement　decreases　with　the　increasing　reverse　pumping　rate.　Under　the　same　reverse　pumping　rate,　the　final　extraction　displacements　for　the　RSC　and　MSC　installed　by　suction　are　lower　than　those　for　the　RSC　and　MSC　installed　by　jacking.　The　final　extraction　displacement　of　MSC　is　almost　equal　to　that　of　the　RSC　with　the　same　internal　compartment　length.　Based　on　the　force　equilibrium,　a　method　of　estimating　the　maximum　extraction　displacement　is　proposed.　It　has　been　proved　that　the　proposed　method　can　rationally　predict　the　maximum　extraction　displacement　and　the　corresponding　over-pressure.　©　2021,　Chinese　Ocean　Engineering　Society　and　Springer-Verlag　GmbH　Germany,　part　of　Springer　Nature.