Transparent UV protective coatings were developed by incorporating nano-TiO2 into waterborne acrylic systems to provide long-term UV protection for UV sensitive cool color roofing. Water based high crystalline TiO2 nanoparticle suspension was prepared via a gel-sol method at a basic pH. The TiO2 nanoparticles have an average size of 20 nm and are stable against agglomeration. As prepared TiO2 nanosuspension is ready to be well dispersed in commercial waterborne acrylic resin system without extra surface modification. The fabricated TiO2/acrylic nanocomposite coating achieved an UV cut-off below 350 nm with a visible transmission greater than 85% at 700 nm. It is also demonstrated that surface modification of Nano-TiO2 with a SiO2 insulation layer would suppress the catalytic activity of Nano-TiO2 and improve the UV protection for UV and photocatalysis sensitive dyes.