The interphase between nano-filler and rubber matrix, also known as “bound rubber (BR)” play an important role in the properties of rubber nanocomposites. Herein, we developed a new method to quantitatively identify the interphase of silica/rubber nanocomposites and carbon nanotubes (CNTs)/ rubber compositesat nanoscale resolution by using peak force quantitative nanomechanical mapping (PF-QNM) mode of Atomic Force Microscope. The modulus and adhesion distribution around the fillers of the composites at nanoscale resolution was measured, and accordingly the interfacial thickness between rubber and fillers with or without silane coupling agent modification was tested according to the gradient change in nanomechanical properties from matrix to fillers. We further studied the effect of physical and chemical charateristic of fillers and rubber macromolecules on the interfacial thickness of rubber nanocomposites. Interestingly, the double layer structure of interphase was directly identifiedin silica/rubber nanocomposites based on PF-QNM images and the corresponding force-distance curves, and was further evidenced by high resolution transmission electron microscopy. This study provides a new method to quantitative characterizethe interface between filler and elastomer matrix at nanoscale resolution.