Nanodiamond composite (NDC) films deposited on silicon substrates by coaxial-arc-plasma-deposition at room temperature are easily peeled off with increasing film thickness. This research adapted additional NDC intermediate layers deposited at high temperatures, to induce atomic-interdiffusion towards the Si substrates, which effectively enhances the adhesion of the intermediate layers with the substrates. In addition, the intermediate layers exhibit low residual stresses and hardnesses, and they can relieve large stresses of the top hardlayers. Consequently, the deposition of 1.5 μm thickness and 55 GPa hardness of NDC films on silicon substrates is possible, which opens up their applications in micro-electro-mechanical-systems and biosensors.