Changes in plant phenology directly manifests the change of climate, especially climate warming. The changes in rhythm of plant growth may alter plant-environment relationships, hence the mass cycles, such as water and carbon, in the ecosystem. Individual plant species respond to climatic changes differently, which may cause great changes in competition and dependence among different species and plant-animal interactions. In the past few years, many reports showed that the plant phonology toward early in spring and late in autumn in Europe, America, and Asia. The changes in plant phenology result in a lengthening growing season, and indicate a warming climate. Phenological model is an important component of ecosystem productivity models, which may play a key role in analysis of vegetation-atmosphere interactions.