A new complexing agent-assisted homogeneous precipitation technology was successfully developed to synthesize Co2+-Ni2+Fe3+-CO32- LDHs materials with high crystallinity and well-defined hexagonal shapes. An experiment to trace changes of phase composition, morphological features of crystallinity, molar ratio of Co2+/Ni2+/Fe3+, and the pH changes in the reaction system was designed to investigate the formation process of Co2+-Ni2+Fe3+-CO32- LDHs materials. The formation process was proposed on the basis of the experimental results. In the case of no TSC added, Fe3+ ions in the reaction system precipitated to Fe(OH) 3 at low pH value, and the Fe(OH)(3) is hard to convert to Co2+-Ni2+Fe3+-CO32- LDHs materials of highly crystalline and regular shapes with free Co2+ and Ni2+. In addition, beta-Ni(OH)(2) as an impurity phase is easily formed in company with the formation of Co2+-Ni2+Fe3+-CO32- LDHs. When TSC is added and optimized amount was 0.6-1.0 mmol L-1, a parts of Fe3+ ions complex with TSC form the [Fe(C6H4O7)(2)](5-) ligand ions and reduce the amount production of Fe(OH)(3), causing pH deposition range of Fe3+ rise. Moreover, the formed [Fe(C6H5O7)(2)](5-) ligand ions changed the direct conversion process of Fe(OH)(3) to Co2+-Ni2+Fe3+-CO32- LDHs, which reacted with free Co2+, Ni2+ ions and formed Co2+-Ni2+Fe3+-CO32- LDHs materials with high crystallinity and well-defined hexagonal shapes in the higher pH value of the reaction system. While TSC optimized amount has more than 1.5 mmol L-1, the excess TSC also complex some of Ni2+ ions except for Fe3+ in the solution and also induce pH deposition range of Ni2+ raise, which is not favorable to formation of Co2+-Ni2+Fe3+-CO32- LDHs material because Ni2+ still existed in the complex form even in the higher precipitation pH value of the reaction system.