Two new three-dimensional coordination polymers, Na [M(nta)]·H 2O(M=Co, Ni) were hydrothermally synthesized and their structures were solved by single-crystal X-ray diffraction. Their structures were analogous and the two crystals belong to the orthorhombic system with space group P2 1, and cell parameters a=0.785 7(9) nm, b=0.974 3(12) nm, c= 1.219 0(18) nm, V=0.933 4(2) nm 3, Z=4 for Na [Co(nta)]·H 2O and a=0.796 7(16) nm, b= 0.975 2(2) nm, c=1.218 2(2) nm, V=0\^946 5(3) nm 3, Z=4 for Na [Ni(nta)]·H 2O. The structures of the title compounds are considered to be four M(nta) - octahedra connected by the sodium atoms, thus the three-dimensional tunnels were formed. Variable temperature magnetic susceptibility indicates that the antiferromagnetic interaction exists in Na[Co(nta)]·H 2O and Na [Ni(nta)]·H 2O.