A two-dimensional Cd(Ⅱ) coordination polymer, [Cd(dtb)]n (dtb = 5,5 '-dithiobis(2- nitrobenzoic acid), has been solvothermally synthesized and characterized by elemental analysis, IR, TG analysis and single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic P21/c space group, with a = 10.7147(10), b = 7.4518(7), c = 22.053(2) A, β = 95.477(2)°, V = 1752.7(3) A3, Z = 4, Mr = 524.74, Dc= 1.989 g/cm3 and F(000) = 1032. The final R = 0.0453 and wR = 0.1201 for 2950 observed reflections with 1 〉 2σ(I). In the complex, the Cd(Ⅱ) ion is coordinated with six oxygen atoms from four different carboxylate groups of dtb ligands and one lattice water molecule. The adjacent Cd centers are interconnected by the flexible carboxylate ligand to form a two-dimensional (2D) structure.