Some play therapist are found to start therapy session without any information about the client, But information about the Client' s present developmental level is essential for therapists to design an optimal play therapy environment So they gather such information from the child ' s parents through interviews or from psychological tests to the child. However, the realiability of the informantion gatered by these methods is controversial. This study reviewed the previous studies, which compared the plays of normal clrildren with developmentally disordered clrildren. It turned out that the normal chilciren's plays differ from the disordered children's plays with respect to the ways of using play tools, play times, and play patterns. This finding is an im])0rtant information for determining both whether a child is disordered and the level of disorder. Sampling from the previous studies, this study summarized play assessment variable ways for constructing a play assessment tools, assessment time and environment, and assessor.