The objective of this study was to develope horticultural therapy program for reducing parenting stress. Parenting stress means negative psychological response of things that should do. This negative response have bad impects to children such as reducing social ability and increasing conduct problems. But parenting stress can be reduced through various parenting education and many program have been practiced to reduced stress. The essence of horticultural therapy is to experience nurturing through growing plants. As a result, horticultural therapy has the philosophical background suitable for introducing horticultural therapy for reducing parenting stress. This study developed cognitive horticultural therapy program with nurturing experience and parent education and applied to seven housewives to it. We used Parenting Stress Index(PSI) in pre-test and post-test for measuring effect and analyzed with Wilcoxon signed rank test. After applying this program eight times for a two-hour session, this study found reduction of parenting stress indicated by 48.14 to 42.57, which was statistically significant(z=-2.117, p<0.05). This study has the limitation of small sample numbers. In the future we should study more horticultural therapy program that affects sub-factors of parenting stress applying more samples.