Dimensional　analysis　can　aid　the　design　of　experiments　and　expression　of　conciseness　of　the　results　generated　by　them.　The　dimensionless　groups,　which　are　the　output　of　a　successful　dimensional　analysis,　are　usually　developed.　This　paper　takes　the　ground　bearing　strength　test　as　the　example,　shows　the　Buckingham＇s　π　theorem　and　improves　the　calculating　methods　of　amelioration　by　Butterfield.　The　author　studied　the　model　experiment　of　siphon　drainage　technology　on　the　bank　slope　by　numerical　simulation　and　validated　the　results　of　dimensional　analysis,　and　proposed　suggestions　for　the　model　experiment　essential　parameter　selection.