This study addressed the effects of environmental attitude improved using forest environmental interpretation program. While previous research has focused developing interpretation program itself, this study analyzed the effects that environmental interpretation has improved toward pro-environmental attitude. This program was designed self-guiding interpretive techniques at Mt. Palgongsan Provincial Park. Environmental attitude was measured using 12 statements which was based on fifth-graders attitude scale in U.S.A. Data were collected from 84 elementary school participants in this program. Results showed that attitude scores of participants increased toward pro-environmental attitude. Especially, three statements (interest, safe and benefits of forest) are statistically significant differences between pre- and post survey. Results can be used by outdoor educators to evaluate and plan their environmental interpretation programs and methods.