This research designed a judgment task experiment of emotion drawings. Fourteen pairs of drawings of happy trees and sad trees were designed, and 240 subjects were randomly selected in Taipei area (30 subjects each from children and adolescents, age 4,5,6,7,9,11,14 and 16) to participate in the experiment. Each subject selected in the research was asked to pick what he (she) thought the happiest tree and the saddest tree. The results of 240 subjects were recorded and the data were categorized and analyzed statistically, to study development of children and adolescents' judgment task in the emotion drawings.