As the perfect combination of strength and luster,silkworm silks have been widely used in many fields.Numerous researches have been conducted to improve its properties for years.This paper demonstrates an in vivo uptake of titanium dioxide(TiO2)nanoparticles by the silkworms,leading to the direct production of intrinsically modified silk.The method easily incorporated the nanoparticles into the inner structure of silks.Results suggest that both the strength and the anti-UV ability of the modified silks were well improved at a low additive amount.