Two kinds of sensitizing dye, acid type (Y=H) and Na salt type (Y=Na) of triphenylmethane dyes such as Rose bengale and tetrabromophenol blue, show different adsorption characteristics on zinc oxide powder in alcoholic solution at 20°C. The difference of adsorption characteristics of dyes on zinc oxide were investigated. The results are: (1) The difference of adsorption activity of xanthenes and phthaleins dyes, which are triphenylmethane group dyes is small. And the difference in adsorption activity of dyes having carboxylic and sulfonic radicals is small too. (2) Acid type and Na salt type dye of xanthenes and phthaleins shows different adsorption characteristics. The acid type dye of xanthenes and phthaleins is more adsorbable than Na salt type dye. (3) The acid type dye which exhibited Langmuir linear relationship from a mono-layer without interaction between the dye molecules. However, Na salt type dye is unsuited to Langmuir equation which is delocalized and is movable in adsorbed state of dyes. (4) Carboxylic or sulfonic radical of dyes will be attracted to adsorption site, and then hydroxyl radical will be attracted with smaller adsorption force than the former radical.