Recently,　perovskite　ferroelectric　photovoltaic　materials　have　been　studied　extensively.　Traditional　photovoltaic　device　usually　uses　the　internal　electric　field　formed　by　PN　junction　to　realize　the　separation　of　photogenerated　carriers　to　form　the　photovoltaic　effect,　while　ferroelectric　material,　due　to　the　existence　of　spontaneous　polarization,　can　spontaneously　realize　the　separation　of　photogenerated　electrons　and　holes　without　the　formation　of　PN　junction,　presenting　the　ferroelectric　photovoltaic　effect.　Chalcogenide　perovskite　with　suitable　band　gap　and　visible　light　absorption　is　expected　to　be　a　new　generation　of　ferroelectric　photovoltaic　materials.　However,　its　application　is　limited　due　to　the　lack　of　ferroelectric　properties.　Hybrid　improper　ferroelectricity　(HIF)　in　layered　perovskites　has　opened　a　new　way　for　developing　the　new　ferroelectrics.　In　contrast　to　the　proper　ferroelectricity　in　which　the　polarization　is　the　main　order　parameter　as　the　driving　force,　the　improper　ferroelectricity　possesses　the　ferroelectric　polarization　that　becomes　a　secondary　order　parameter　induced　by　other　orders.　In　this　work,　we　study　the　ground　state,　electronic　structure　and　hybrid　improper　ferroelectricity　of　n　=　2　Ruddlesden-Popper　(RP)　Sr3B2Se7　(B　=　Zr,　Hf)　based　on　the　first　principles.　The　total　energy　calculations　and　phonon　spectrum　analysis　show　that　the　ground　state　of　Sr3B2Se7　(B　=　Zr,　Hf)　is　of　A2(1)am　polar　phase.　The　hybrid　improper　ferroelectricity　originates　from　the　coupling　between　two　rotation　modes　of　BSe6　octahedron.　Electronic　structure　calculations　show　that　Sr3Zr2Se7　and　Sr3Hf2Se7　are　semiconductors　with　direct　band-gaps,　which　are　around　1.56　eV　and　1.84　eV,　respectively.　The　ferroelectric　polarization　values　calculated　by　the　Berry　phase　method　are　around　12.75　mu　C/cm(2)　and　9.69　mu　C/cm(2),　respectively.　The　contribution　of　each　atomic　layer　to　the　ferroelectric　polarization　is　investigated　when　the　Born　effective　charge　method　is　used.　The　results　show　that　the　polarization　of　Sr3B2Se7　(B　=　Zr,　Hf)　mainly　comes　from　the　Sr-Se　atomic　layers.　To　sum　up,　Sr3B2Se7　(B　=　Zr,　Hf)　show　strong　ferroelectric　polarization　and　good　visible　light　absorption　characteristics　and　they　are　expected　to　be　candidates　of　a　new　generation　of　ferroelectric　photovoltaic　materials.