The nano-TiO_2 power is dispersed into traditional exterior wall coatings by surface-active agent,super shear instruments and ultrasonic dispersions,the properties of the coatings are studied.The experiments show that the overall properties of the coatings are evidently improved with addition of 0.5%wt dispersed nano-TiO_2 powders.This paper discussed the suitable dosage of nano-TiO_2 and its adaptability to the latex.