In　the　design　of　soft　body　armors　for　ballistic　protection,　the　blunt　trauma　effect　has　to　be　taken　into　account　and　it　is　usually　evaluated　by　the　back　face　deformation　(BFD).　Most　of　the　current　research　on　blunt　trauma　is　based　on　experiments　and　simulations,　whereas　the　development　of　analytical　models　is　still　rare.　This　study　develops　an　analytical　model　to　predict　BFD　for　a　hybrid　panel　composed　of　modified　aramid　fabrics　and　Ultra-high　molecular　weight　polyethylene　(UHMWPE)　unidirectional　sheets,　which　is　based　on　the　two-stage　damage　evolution:　shear　plugging　and　tensile　bulge.　Firstly,　the　shear　and　tensile　energy　of　the　hybrid　panel　as　well　as　the　deformation　energy　of　the　clay　were　constructed.　Secondly,　the　characteristic　equations　were　developed　according　to　the　law　of　energy　conservation　and　BFD　could　be　obtained　by　solving　the　equations.　The　results　of　the　analytical　model　were　found　to　be　in　good　agreement　with　experiments　and　FE　simulations.　With　the　assistance　of　the　model,　the　effect　of　projectile　geometry　and　optimized　designs　for　hybrid　panels　have　been　studied.