The invention discloses a layered porous material for adsorbing and separating allylene and propylene, which has periodic intra-layer rhombic pore channels and interlayer broken line type pore channels, is formed by metal ions M, inorganic anions A and organic ligands L through coordination bonds and supramolecular action, and has a structural general formula of ML2A, wherein the metal ion M is atleast one of Fe<2+>, Co<2+>, Ni<2+>, Cu<2+> and Zn<2+>, the inorganic anion A is at least one of TiF6<2->, GeF6< 2->, NbOF5<->, ZrF6<2-> and SnF6<2->, and the structural formula of the organic ligandL is shown in the specification, wherein R1 to R8 are independently selected from H, F, Cl, Br, I, CH3, NH2, OH or COOH respectively. The invention further discloses a method for adsorbing and separating allylene and propylene, the layered porous material is used as an adsorbent, the adsorbent is in contact with mixed gas containing allylene and propylene, allylene is selectively adsorbed, and separation of allylene and propylene is achieved.