This study has proposed a model of group horticultural therapy to be presented the process of group horticultural therapy, the group development stage, its therapeutical factors, its horticultural therapy intervention and instructions of appropriately performing operations in accordance with reorganizing the group horticultural therapy with proper consideration for individuals or groups. This attempt is believed to see higher than the effects of treatment with group dynamics and the group development stage considering that horticultural therapists can perform group horticultural therapy from individuals. In this study, the group development stage of group horticultural therapy based on steps of Corey(1995) is consist of 4 stages: initial stage(orientation and exploration), conflict stage(dealing with resistance), working stage(cohesion and productivity), final stage(consolidation and termination). This study has presented the treatment factors and horticultural therapy intervention in the form of group horticultural therapy along the steps of the group development stage. However, this model of the group horticultural therapy is considered the conceptional frame works through the reference review. To conclude, after practical application being analyzed the type of group, the succeeding study of the effect which reveals reflected and amended model is necessary.