Antireflective (AR) coatings, which can suppress the undesired interfacial Fresnel reflections, are widely used in optical devices and energy-related instruments. Conventional single-layer quarter-wave AR coatings, which only work at a single wavelength, have been seriously limited in some practical applications because of this inherent property. In this work, broadband AR coatings were designed and prepared based on the concept of λ/4-λ/2 double-layer interference film by Sol-Gel dip-coating method. Substrates (K9 glasses) coated with the double-layer films attained consistent high transmittances at 500-700 nm with an average transmittance of 99.4%, and the average transmittance at visible region was 99.0%. The λ/4-λ/2 broadband antireflective coatings were achieved without low-refractive- index materials. So high-refractive-index TiO₂ could be introduced into the double-layer films to endow the films with self-cleaning property. The double-layer films exhibited outstanding superhydrophilicity with water contact angle of 2.2° in 0.5 s, and the superhydrophilicity lasted for 20 d in the absence of UV illumination. The double-layer coatings also showed a good ability to decompose organic substances under UV irradiation. The broadband of AR coatings with photocatalysis and durable superhydrophilicity may be applied in the fields of opto- and microelectronics.