In our study, air oxidation together with three different procedures for purifying single-walled carbon nanotubes (SWCNTs) was investigated. High purity SWCNTs were obtained. The purified SWCNTs were dispersed into four different types of dispersants and different ratio of SWCNTs to dispersant was evaluated in order to find the optimal condition. Transparent conducting films were fabricated by the purified and well dispersed SWCNT solution. Nitric acid concentration was optimized to enhance the film conductivity. SWCNT films with low sheet resistance and high transmittance were obtained by nitric acid treatment.