The work aims to prepare the thick Ni-diamond composite coating on hard alloy matrix by electrochemical depo-sition. The binding strength and thickness of composite coating were improved by introducing the intermediate composite layer. The bonding strength and grinding performance of thicker coating were investigated by thermal shock test and tribological test. From the analysis on section, micro morphology, surface crack distribution and the bonding state between diamond particles and matrix metals, the thickness of the normal coating was about 30 μm and the thickness of the multi-layer structure coating was about 50 μm which was nearly doubled. No cracks were found on the surface of the two types of coatings after five thermal shocks. Cracks appeared in both coatings after 20 thermal shocks. After 25 thermal shocks, the crack width of the normal coating became larger and the crack of the multi-layer structure coating only appeared in the sub-surface layer, but there was no crack in the surface layer. After GCr15 was ground for 2500 m, the gap between diamond particles and matrix metals in the normal coating increased and the nearby Ni layer broke. The gap between diamond particles and matrix metals in the multilayer structure coating was still small, with only a few intermittent small cracks and the Ni layer nearby was not affected. The wear rate of material couplers of multilayer structure coating was higher than that of normal coating. The internal stress of Ni-diamond composite coating can be reduced by multilayer structure design. Then the goal of thickening the coating is achieved. The interface bonding strength of the thickened Ni-diamond composite coating does not decrease, but the diamond particles are more uniform and compact and at the same time the coating has better grinding performance.