A novel 1D coordinated polymer, {[NaNi(mal)2(μ‐H2O)(H2O)3] · (H2O)2}n (H2mal=malonic acid), has been synthesized and its crystal structure is determined by X‐ray diffraction analysis. Its crystal structure belongs to orthorhombic system with space group p2(1)2(1)2(1). The coordination environment around Ni(II) is described as a distorted octahedron constructed by four oxygen atoms from two trans‐coordinated malonates and two oxygen atoms from two trans‐coordinated water, in which oxygen atom of one water molecule bridges adjacent Ni2+ and Na+. Seven coordination environments around Na center are constructed by four oxygen atoms from four malonates and three oxygen atoms from three water molecules. In the crystal structure of title complex there are complicated hydrogen bonds. [ABSTRACT FROM AUTHOR]