Through the combing of the horticultural therapy system and based on the experience of participating in the American horticultural therapist registration certification courses and internship, this paper systematically analyzes the basic components, essential connotations, and implementation applications of foreign horticultural therapy from three levels: horticultural therapist team training, horticultural therapy program development, and natural healing environment planning, which also reveals their interrelationships and roles, as well as their essential functions in building a perfect high-quality horticultural therapy system. Finally, based on the development review and prospects of horticultural therapy in China, it is proposed to promote a certification system for forest garden health therapists, relying on the forest therapy and Professional Committee of Horticultural Therapy, which makes use of healing environment and healing landscape construction, as well as a wide range of natural healing practice activities to further jointly weave a complete public health and recreation service system, which is conducive to promoting the public health and well-being of the whole people.