In order to reveal the relationship between modulation structure and superhardness effect, a series of c-VC/h-TiB2 nanomultilayers with different modulation structures is synthesized by magnetron sputtering technique. X-ray diffractometer, high-resolution transmission electron microscope and nanoindention device are employed to investigate the microstructures and mechanical properties of the multilayers. Based on the experimental results, a relation map of modulation structure and superhardness effect is established for the nanomultilayer composed of c-VC and h-TiB2 with four regions. In these regions, superhardness effect could be generated only in the region with sharp interface and coherent growth structure. In other regions, the change of modulation structure leads to the change of the microstructure, and the hardness will decrease accordingly. The map could provide reference for obtaining superhardness effect by designing modulation structure in those analogous heterogenous nanomultilayers.