The effects of climate warming on plant phonological changes from 1983 to 2004 in Guangdong are studied by use of the plant phenological data and temperature data of 10 Agrometeorological stations in Guangdong of the same time. The models for relationship between phenological periods and temperature are constructed. The responses of the phenological period to climate change are ana lyzed. The results show that the phenological periods of ligneous plants occurred earlier with increasing temperature in spring; on the contrary, the ligneous plant phenological periods delayed with decreasing temperature. The response of plant phenological periods to climate change is nonlinear. In the context of the same range of temperature rise or fall, the range of phonological period postpone as a result of the temperature fall is greater than that of phonological period advance as a result of temperature rise.