A new three dimensional layered cobalt phosphate complex Co3(PO4)2·6H2O, was prepared by hydro-thermal reaction of Co(CH3COO)2·4H2O and H3PO4, NH4VO3. The crystal structure of the complex was deter-mined by single-crystal X-ray diffraction. The result indicates that it crystallizes in the tetragonal space group I4/m. It rarely occurs in cobalt phosphate complex to form two kinds of coordinate geometry of Co(Ⅱ), six water molecular oxygen atoms surround Co(Ⅱ) and form an octahedron geometry, Co(2) bond to four oxygen atoms from 4PO43- and one water molecular oxygen and build a tetragonal pyramid. The kinetic study shows that the first decomposition stage is governed by A B C mode. CSD: 414600.