A separator for a secondary battery, comprising: a porous substrate having a pore; a first porous coating layer formed by coating on at least one area among at least one surface and the pore of the porous substrate, and including first inorganic particles having a Brunauer, Emmett & Teller surface area less than or equal to 10 m 2 /g and a first binder polymer disposed in a part or all of the first inorganic particles to couple and bond the first inorganic particles to one another; and a second porous coating layer formed by coating on the first porous coating layer, and including second inorganic particles having a BET surface area in a range of 12 to 30 m 2 /g and a second binder polymer disposed in a part or all of the second inorganic particles to couple and bond the second inorganic particles to one another, wherein the second inorganic particles have an average pore size in a range of 2 to 200 nm, wherein the porous substrate is a polymer membrane, a multi-layered polymer membrane, or a woven or non-woven fabric formed from any one polymer selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenyleneoxide, cyclic olefin copolymer, polyphenylenesulfide, and polyethylenenaphthalene, or mixtures thereof; wherein the first inorganic particles and the second inorganic particles are independently selected from the group consisting of BaTiO 3, Pb(Zr x,Ti 1-x)O 3 (PZT, 0<x<1), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT, 0<x<1, 0<y<1), (1-x)Pb(Mg 1/3 Nb 2/3)O 3-x PbTiO 3 (PMN-PT, 0<x<1), hafnia (HfO 2), SrTiO 3, SnO 2, CeO 2, MgO, NiO, CaO, ZnO, ZrO 2, SiO 2, Y 2 O 3, Al 2 O 3, SiC and TiO 2, or mixtures thereof and/or the group consisting of lithium phosphate (Li 3 PO 4), lithium titanium phosphate (Li x Ti y (PO 4) 3, 0<x<2, 0<y<3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4) 3, 0<x<2, 0<y<1, 0<z<3), (LiAlTiP) x O y -based glass (0<x<4, 0<y<13), lithium lanthanum titanate (Li x La y TiO 3,0<x<2,0<y<3), lithium germanium thiophosphate (Li x Ge y P z S w, 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li x N y, 0<x<4, 0<y<2), SiS 2 (Li x Si y S z,0<x<3,0<y<2,0<z<4)-based glass and P 2 S 5 (Li x P y S z, 0<x<3, 0<y<3, 0<z<7)-based glass, or mixtures thereof; wherein the first inorganic and the second inorganic particles independently have an average particle diameter in a range from 0.01 to 10 μm. a porous substrate having a pore; a first porous coating layer formed by coating on at least one area among at least one surface and the pore of the porous substrate, and including first inorganic particles having a Brunauer, Emmett & Teller surface area less than or equal to 10 m 2 /g and a first binder polymer disposed in a part or all of the first inorganic particles to couple and bond the first inorganic particles to one another; and a second porous coating layer formed by coating on the first porous coating layer, and including second inorganic particles having a BET surface area in a range of 12 to 30 m 2 /g and a second binder polymer disposed in a part or all of the second inorganic particles to couple and bond the second inorganic particles to one another, wherein the second inorganic particles have an average pore size in a range of 2 to 200 nm, wherein the porous substrate is a polymer membrane, a multi-layered polymer membrane, or a woven or non-woven fabric formed from any one polymer selected from the group consisting of polyethylene, polypropylene, polyethyleneterephthalate, polybutyleneterephthalate, polyester, polyacetal, polyamide, polycarbonate, polyimide, polyetheretherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenyleneoxide, cyclic olefin copolymer, polyphenylenesulfide, and polyethylenenaphthalene, or mixtures thereof; wherein the first inorganic particles and the second inorganic particles are independently selected from the group consisting of BaTiO 3, Pb(Zr x,Ti 1-x)O 3 (PZT, 0<x<1), Pb 1-x La x Zr 1-y Ti y O 3 (PLZT, 0<x<1, 0<y<1), (1-x)Pb(Mg 1/3 Nb 2/3)O 3-x PbTiO 3 (PMN-PT, 0<x<1), hafnia (HfO 2), SrTiO 3, SnO 2, CeO 2, MgO, NiO, CaO, ZnO, ZrO 2, SiO 2, Y 2 O 3, Al 2 O 3, SiC and TiO 2, or mixtures thereof and/or the group consisting of lithium phosphate (Li 3 PO 4), lithium titanium phosphate (Li x Ti y (PO 4) 3, 0<x<2, 0<y<3), lithium aluminum titanium phosphate (Li x Al y Ti z (PO 4) 3, 0<x<2, 0<y<1, 0<z<3), (LiAlTiP) x O y -based glass (0<x<4, 0<y<13), lithium lanthanum titanate (Li x La y TiO 3,0<x<2,0<y<3), lithium germanium thiophosphate (Li x Ge y P z S w, 0<x<4, 0<y<1, 0<z<1, 0<w<5), lithium nitride (Li x N y, 0<x<4, 0<y<2), SiS 2 (Li x Si y S z,0<x<3,0<y<2,0<z<4)-based glass and P 2 S 5 (Li x P y S z, 0<x<3, 0<y<3, 0<z<7)-based glass, or mixtures thereof; wherein the first inorganic and the second inorganic particles independently have an average particle diameter in a range from 0.01 to 10 μm.