The application of nanosilica in high performance tire highly depends on its uniform dispersion in rubber matrix. A series of dispersible nanosilica (denoted as DNS) modified by diphenyl guanidine (denoted as DPG, a vulcanization accelerator) were synthesized by liquid phase in situ surface chemical modification. The structure of the as-obtained DNS-DPG fillers was investigated in relation to Fourier transform infrared spectrometric analysis, thermogravimetric analysis, dynamic light scattering test, and transmission electron microscopic observation. It was found that the rubber vulcanization accelerator DPG was successfully grafted onto the surface of nanosilica, thereby effectively preventing the silica nanoparticles from agglomeration and significantly reducing the average particle size. The reinforcing effect of the DPG-modified DNS nano-fillers for the solution polymerized styrene butadiene rubber/butadiene rubber (denoted as SSBR/BR) was dependent on the fraction of the modifier DPG; in particular, when the amount of modifier DPG is 135.25 mmol/kg (denoted as DNS-DPG-3), silica exhibited very homogeneous dispersion in the SSBR/BR matrix, which contributed to significantly enhancing the filler-rubber compatibility. As a result, SSBR/BR/DNS-DPG-3 nanocomposite exhibited the best mechanical properties, integrated high abrasion resistance and low rolling resistance. The modified silica not only possessed the effect of accelerating the crosslinking reaction, but also showed the reinforcing effect. This could make it feasible for SSBR/BR/DNS-DPG nanocomposite to find promising application in green tire tread. POLYM. ENG. SCI., 59:1270-1278 2019. (c) 2019 Society of Plastics Engineers