Firstly,　an　indoor　model　test　was　modeled　by　using　the　large-scale　all-purpose　finite　element　software,　ABAQUS　and　3D　finite　element　method　to　verify　the　reliability　of　the　stability　analysis　of　cave　structures.　Then,　based　on　the　karst　geological　data　of　the　contract　section　A11　in　Yongan-Wuping　highway,　the　karst　caves　were　approximately　regarded　as　the　ellipsoids　and　the　3D　finite　element　models　were　established　to　analyze　how　the　stability　of　the　embankment　and　the　karst　cave　roof　is　influenced　by　roof　thicknesses,　filled　heights,　karst　cave　locations　and　filling　conditions　of　karst　caves.　Also,　the　2D　plain　strain　finite　element　method　was　adopted　to　make　a　comparison　with　the　prevailing　method　for　safe　thicknesses　of　karst　cave　roofs.　Research　shows　that,　for　cave　roof　strata　which　are　relatively　intact,　the　safe　thicknesses　of　cave　roofs　obtained　by　using　4　as　the　stability　factor　of　safety　of　roof　tensile　failure　are　too　conservative.　The　safe　thicknesses　of　cave　roofs　obtained　by　the　beam-slab　theory　of　bending　tensile　failure　are　inclined　to　be　conservative　too.　This　is　because　the　actual　roof　strata　do　not　coincide　completely　with　simplified　hypothesises　of　the　beam-slab　theory.　However,　based　on　the　beam-slab　theory　of　bending　tensile　failure,　the　safe　thicknesses　calculated　by　the　maximum　bending　moments　obtained　from　the　finite　element　analysis　are　the　most　economical.　For　actual　karst　caves　which　have　obvious　3D　effects,　the　prevailing　simplified　theory　and　2D　numerical　analysis　method　are　relatively　coarse　and　the　3D　numerical　analysis　method　should　be　adopted.　Through　analyzing　the　above　problems,　the　research　work　offers　guidance　to　the　embankments　design　and　karst　cave　treatment　of　the　highway　in　the　karst　regions.　Good　socioeconomic　benefits　are　obtained.　It　can　be　used　as　a　reference　for　similar　engineering　application.