This article describes the process of using therapeutic play to reduce the stress of a preschool child at a hospital. Data were collected through participant observation and interviews between December 1 and 8, 2012. Seven processing regarding the reaction of the child and the interaction between the child and the family were analyzed. The results indicated that the child's stress of hospitalization included separation anxiety, fear of invasive treatment, and loss of control. On the basis of preschool children's cognitive development characteristics, the author used emotional outlets and incorporated instructional and physiologically enhanced play into the nursing process to assist children in relieving internal conflicts and stress, thereby improving self-confidence and self-control. Such play could help children accept various treatments and promote children's adaptation during hospitalization and after discharge.