VN/SiO2 nanomultilayers with different individual SiO2 and VN layer thicknensses were prepared with V and SiO2 targets by reactive sputtering. The microstructure and mechanical properties of the films have been studied by X-ray diffraction, energy dispersive X-ray spectrometry, high-resolution transmission electron microscopy and nanoindentation. The results reveal that the SiO2 film synthesized by radio frequency reactive sputtering in Ar-N2 gas mixture contains no N element, normally amorphous SiO2 is forced to crystallize at very low layer thickness (2 layer gradually forms an amorphous structure and blocks the coherent growth of nanomultilayers, and the hardness of nanomultilayers gradually decreases. On the other hand, the changing of VN layer thickness has relatively small effects on the microstructure and mechanical properties of nanomultilayers.