Adding nano-fillers into plastic matrix have been proved to be a possible way to reinforce polymeric materials. However, it is difficult to simultaneously improve the toughness and stiffness. To fix this, we herein provide a simple and efficient method-adding 8 phr elastomer-chlorinated polyethylene (CPE) and 5 phr nano-silicon dioxide (nano-SiO2) particles into poly(acrylonitrile-styrene-acrylic) (ASA) matrix. By such a simple combination, the impact strength, tensile and flexural strength were enhanced by 82.7%, 22.7%, and 30.7%, respectively. It was demonstrated that the self-formation of CPE network assisted by nano-SiO2 was responsible for the improved mechanical performance. Four issues are considered to be responsible for the self-formation of network: the increase in the viscosity, the decrease in the elasticity of nano-SiO2-localized ASA phase, the effect of nano-SiO2 on distracting the molecular interactions between CPE and ASA, and the interfacial adhesion. Our present study provides an easy and effective route toward polymeric materials with simultaneous improved toughness and stiffness. (C) 2015 Elsevier B.V. All rights reserved.