The purpose of this study was to examine the effects of picture book programs on sexual interaction knowledge and attitude for vocational high school students with moderate intellectual disabilities. A single-subject experimental study of multiple probe design across behaviors was used to evaluate the effects on two participants who were selected from a special education high school. The independent variable was the picture book programs and the dependent variables were the effects of sexual interaction knowledge and attitude. Three main themes of instructions were included "physical and psychologic knowledge of sexuality", "sexual interactions" and "sexual intimacy and self-protection". The findings were presented as follows: (1) Picture book programs had significantly immediate and retentive effects on increasing the rate of accuracy on "physical and psychologic knowledge of sexuality" for two participants. (2) Picture book programs had significantly immediate and retentive effects on increasing the rate of accuracy on "sexual interactions" for two participants. The retentive effects of this theme were found little lower than "physical and psychologic knowledge of sexuality" and "sexual intimacy and self-protection". (3) Picture book programs had significantly immediate and retentive effects on increasing the rate of accuracy on "sexual intimacy and self-protection" for 2 participants. (4) Picture book programs had the teaching effects on "the attitude of sexual interaction" from medium to high degree for two students with moderate intellectual disabilities. And the attitude continued toward positive change. (5) Picture book programs had significantly retentive effects on "the attitude of sexual interaction" for two participants.