The purpose of this study is to apply play therapy self-efficacy training program to play therapist to verify its effectiveness. 26 play therapists with <3 years of clinical career were divided into the experimental (N=13) and control groups (N=13). The training programs applied to experimental groups were basic training, planning training, intervention training, and supervision training. To determine the effects of the program, the data were processed by using SPSS 23.0 to perform repeated measure ANOVA. This study obtained the following results: this play therapist training program improved self-efficacy related to micro skill, counseling process, and dealing with difficult client behavior in the experimental group. It is significant in that it applied this training program to play therapists and confirmed its effectiveness in improving self-efficacy.