Net photosynthetic rate and dark respiratory rate of sun leaves of two species of Ligustrum gorwing in Xuzhou were measured with GH Ⅲ photosyhthetic of meter in four seasons of a year. And chlorophyll content was measured with colorimetric analysis method.Photosynthetic temperature optima,respectively,was also measured at different temperatures in four seasons.The results showed that all of index of two plants measured had a seasonal changes. In natural environment,the highest values of photosynthetic r...