Treatment of bis(2-dimethylaminoethyl) ether(BDMAE) with nickel acetate afforded a novel 3D nickel(Ⅱ) complex [Ni(BDMAE)(H2O)3·(CH3COO)2·(H2O)2] under solvothermal conditions. Its crystal structure was characterized by elemental analysis, IR spectrum, PXRD and single-crystal X-ray diffraction analysis. The complex belongs to the orthorhombic system, space group C2221 with a=8.823(2), b=13.932(3), c=17.563(4) , V=2158.9(8) 3, Z=4, C(12)H(36)N2NiO(10), Mr=427.14, Dc=1.314 g/cm3, F(000)=920 and μ=0.944 mm(-1). Single-crystal X-ray diffraction reveals that the mononuclear nickel(Ⅱ) ion is six-coordinated to one oxygen, two nitrogen atoms of the BDMAE ligand and three oxygen atoms of coordinated water molecules. The complex exhibits a 3D supramolecular structure through a variety of intermolecular and intramolecular hydrogen bonding interactions. In addition, the complex has been investigated for catalytic properties towards the Henry reaction of nitromethane with p-nitrobenzaldehyde, and the results indicated that the 1-p-nitrophenyl-2-nitroethanol product was obtained in excellent yield under optimum conditions with the complex as the catalyst.