Recently the relations between person and person have become thinner and more closed ; therefore the improvement of human relations was necessarily indicated in various circumstances. In 1989, "Human Relations" became a new curriculum of Kindergarten education and in 1992, a new subject "Seikatsuka" was set up in the elementary school curriculum. These new attempts in school education are to develop and strengthen human relations among children. We have already begun to organize a group for three-years-old children and their mothers. This group activity is based on a theory : Science of Relationships which was founded by Prof. Kohei Matsumura. Its purpose is to create the co-cross-being situation of Self, Person and Object among humans. In our group activities, we set up various kinds of situations for the three-years-old childen in order to have them experience the co-cross-being situation of Self, Person and Object. In this study, we report the results of a special program called "Psychodrama for childen an mothers" conducted since 1983. In this report, we focus on the following two points ; (1) the purposes and features of our group activities. (2) the meanings of human relations in our group activities.