The purpose of this research was to investigate the effect of horticultural therapy for children of developmental disability. Drawing was used as a supplementary evaluation scale because the disbilitty had many difficulties to express how they felt when they had horticultural therapy. Children with developmental disability could express their states and conditions by drawing a picture after horticultural therapy; a drawing could be a supplementary scale to communicate their interactions. This study showed that the integrative horticultural therapy combined with art therapy technique improved the effectiveness of horticultural therapy; the integrated therapy gave the disability a synergy effect of not only a supplementary evaluation scale but also a therapeutical stimulation.