Reinforcing and toughening poly (phenylene sulfide) (PPS) with rigid SiO2 nano-particles was realized simultaneously under the suitable thermodynamic state of PPS, and the key issue about the effect of matrix/filler interaction was also demonstrated. The strong matrix/filler interaction realized by grafting reactive groups onto nanoparticles was beneficial for stress transfer and thus in favor of the increase in tensile strength of PPS. Meanwhile, this interaction provided nanoparticles with certain mobility to move with molecular chains and align along the tensile direction when T > T-g of PPS, thus the nanoparticles could significantly improve the tensile toughness of PPS according to the energy dissipation mechanism. Consequently, the tensile strength and elongation to break values of PPS increased to 59.0 MPa and 112.1 % from the initial values of 48.0 MPa and 78.5 % by adding 1 wt% grafted SiO2 nano-particles. The work provided a promising method to reinforce and toughen rigid-chain polymer simultaneously and prepare high-performance PPS nanocomposites.