Abstract: Arnold Arboretum in Harvard University is an important institution in the United States for collecting and studying Chinese plants. From the early 20th century, a group of Chinese scholars came to study and work there for the purpose of introducing western plant science to China. After returning China, they began to teach students, establish institutions, and study Chinese plants. They pioneered plant science in China. Arnold Arboretum is deemed as an origin of Chinese plant science. The findings, methods and even the way of building botanical garden of Arnold Arboretum have profound impacts on the development of modern botany in China.