Polyaniline was synthesized by chemical oxidation polymerization, and polyaniline‐silica (PANI‐SiO2) nanocomposites were prepared by precipitation method. A reinforced PANI‐SiO2/HNBR was obtained by filling the PANI‐SiO2 composites into hydrogenated nitrile rubber (HNBR). The amino cations contained in acid‐doped PANI can electrostatically attract SiO32−, so that SiO2 can grow directly on the surface of PANI, thus reducing the agglomeration of silica and improving the mechanical properties of reinforced rubber. The effect of PANI and PANI‐SiO2 composites on mechanical properties of hydrogenated nitrile butadiene rubber was studied. The results show that PANI improves the dispersion of SiO2 in HNBR. When the PANI‐SiO2 composite (PANI content of 2%) in PANI‐SiO2/HNBR is 30 phr, the filler network is the weakest, and the dispersion of filler is the best in rubber, the maximum tensile strength of PANI‐SiO2/HNBR is 30.31 MPa, which is 1.87 times that of SiO2/HNBR, the tear strength is 27.7 MPa, which is 129.4% of that of SiO2 reinforced packing with the same number of components. The hardness and elongation at break both increase. In addition, the permanent tensile deformation of PANI‐SiO2/HNBR is also reduced.