Silaned nano-silicon dioxide (SiO₂) was used to improve the adhesion properties of carbon fibre/polyethylene (CF/PE) composites. The nano-SiO₂ were treated by silane under different discharge time. And the changes on the surface properties of the treated and untreated composites were studied by impact, three-point bending tests and scanning electron microscopic analysis. The measurement showed that CF increases fracture toughness with the increase in CF content. Too much high content of CF did not further cause the increase in the toughness of CF/PE composite. The impact strength of silaned specimens is still higher than those of the unsilaned ones. The modified composite with the good matrix/fibre adhesion possessed 20% higher interlaminar shear strengths than the composite having weak interface.