The silicon dioxide (SiO₂) antireflective coatings which were fabricated by traditional sol-gel method performed excellent antireflective property due to their low refractive index. However, their adhesion was very poor which strictly restricted their application fields. In this paper, organic-bridged polysilsesquioxane EG-BPSQ was introduced into SiO₂ sol to enhance the adhesion between SiO₂ nanoparticles as well as between coating and substrate. By post-treatment of different temperature, a series of antifogging and antireflective coatings with enhanced adhesion were obtained. Furtherly, the effects of EG-BPSQ addition on the microstructure, optical property and adhesion of composite coatings and different post-treatment temperature on the optical property and antifogging property were both investigated. The experimental results showed that EG-BPSQ plays the dual roles of bonding and pore-forming. When the post-treatment temperature was 150℃, the composite coatings not only performed good antireflective property with the transmittance as high as 98.5% which was approximately 8% enhancement compared to that of blank substrate, but also exhibited antifogging property. Besides, all the composite coatings adhesion level was 0 grade.